Pymdown-extensions

Please see [Migration Notes](https://github.com/facelessuser/pymdown-extensions/blob/main/docs/src/markdown/about/releases/9.0.md) for details on upgrading to 9.0.

- **NEW**: Arithmatex: Wrap MathJax "script" format (non-preview) with a container element just like all other
Arithmatex output formats.
- **NEW**: Arithmatex: MathJax (non-generic) form's container element now has the `arithmatex` class added just like
everywhere else.
- **NEW**: Arithmatex: Add options to override HTML element container type of inline and block math.
- **NEW**: Arithmatex: Add new formatter functions intended to replace old math fenced/inline block formatters. New
formatter functions are configurable. All others are marked as deprecated and will be removed at some future date.
- **NEW**: Emoji: Upgraded Twitter emoji database to support latest emoji. It is a known issue that Twitter has
`:man_in_santa_hat:` and `:mx_claus:` backwards -- same for `:mrs_claus:` and `:woman_in_santa_hat:`. That is on
Twitter's side, not ours.
- **NEW**: Highlight: Add support for the Pygments option `linespans`.
- **NEW**: Highlight: Add support for Pygments option `lineanchors`.
- **NEW**: Highlight: Add support for Pygments option `anchorlinenos`.
- **NEW**: Highlight: Remove `legacy_no_wrap_code` option.
- **NEW**: Add support for generating title headers pulled from the Pygments lexer for code blocks. Feature can be
enabled via the new `auto_title` option. If a specific name is not preferred, these names can be overridden via
a user defined mapping called `auto_title_map`.
- **NEW**: SuperFences: Allow setting a title, or overriding an auto title via the new `title` option in a fenced code
header.
- **NEW**: SuperFences: Allow adding ID and arbitrary `data-` attributes on Pygments code blocks. The latter requires
the `attr_list` extension to be enabled.
- **NEW**: SuperFences: Removed old deprecated option `highlight_code` which no longer did anything.
- **NEW**: SuperFences: Remove legacy code meant to help with transitioning to new custom fence function format.
- **NEW**: Tabbed: New alternate style that allows for a scrollable tabs if they overflow. Feature is experimental, see
docs for more information.
- **NEW**: Slugs: Add new configurable `slugify` function that aims to replace all other slugify methods. Deprecate
`uslugify`, `uslugify_encoded`, `uslugify_case`, `uslugify_case_encoded`, `gfm`, and `gfm_encoded`. `slugify` takes
parameters returning a function that performs the desired slug handling. `slugify` adds new options `case="fold"` for
case folding and `normalize='<normalize format here>'` (uses `NFC` by default).
- **FIX**: BetterEm: Fix some complex cases related to "smart" logic. (1413)
- **FIX**: EscapeAll: Fix issue where an escaped HTML entity may end up with incorrect slug and incorrect table of
content entry.
- **FIX**: Highlight: Fix issue that occurs when showing only nth line numbers and using `pymdownx-inline`. Lines not
showing a line number would not render with the proper leading space.

- **NEW**: Snippets: now accepts a list of base paths which will be resolved in the order they are specified.
Compatibility is present with legacy behavior, and a single string path will still be accepted.
- **NEW**: Snippets: allow for specifying certain snippets to auto-append to every file. Useful for appending
abbreviations, reference links, etc.
- **NEW**: Snippets: a snippet base path can be a full path to a file. When a base path is a full path to a file, only
that file will be included from the specified folder. This allows for targeting a one off file outside of the normal
snippet paths(s).
- **NEW**: MagicLink: add GitHub Discussions support to MagicLink. Can now use `?<num>` to link discussions. Full
discussion links will also be shortened if shortening is enabled. (1187)
- **NEW**: MagicLink: add new `normalize_issue_symbols` option to make issues, pull request, and discussion links all
render with `` instead of ``, `!`, and `?` respectively. Input syntax is still the same. Great if you want a GitHub
style look where all issue types are just rendered with ``.
- **FIX**: MagicLink: documentation will not render links with special icons added via CSS so as not to confuse users
that may think that is part of MagicLink. While possible with CSS, MagicLink provides no CSS automatically.
- **FIX**: Tabbed &amp; Details: Fix corner case with lists. (1225)
- **FIX**: Fix issue with unescaping logic in code blocks.

- **FIX**: Ensure content immediately before Details content or Tabbed content gets preserved.
- **FIX**: StripHTML: Fix some corner cases related to stripping comments.

- **NEW**: Drop support for Python 3.5.
- **NEW**: Officially support Python 3.9.
- **NEW**: Tabbed titles can now have simple Markdown in them which can be parsed and rendered (like emoji, bold, etc.).
- **FIX**: Avoid parsing script tags in PathConverter and B64 extensions.

- **FIX**: Fix issue with `pymdownx-inline` an Pygments 2.7+.

Please see [Release Notes](./releases/8.0.md8.0) for details on upgrading to 8.0.

- **NEW**: Added SaneHeaders extension.
- **NEW**: SuperFences \& InlineHilite: gracefully handle failing custom formatters and/or validators. Users should add their own debug code to their formatter/validator if they suspect it isn't working.
- **NEW**: SuperFences: if a custom fence validator fails, try the next custom fence until all are exhausted.
- **NEW**: SuperFences: no longer allow custom options in the form `key=` (no value). Only keys with values or keys with no value and no `=` are accepted. Keys with no value will now assume the value to be the key name.
- **NEW**: SuperFences: if `attr_list` extension is enabled, fenced code that use brace attribute list style headers (` {lang id .class attr=value}`) will attach arbitrary attributes that are included in the header to the code element.
- **NEW**: SuperFences: when Pygments is disabled, options (such as `linenums`) included in fenced code headers no longer do anything. If `attr_list` is enabled, and the brace header is used, such options will be treated as HTML attributes. JavaScript highlighter options should be defined in the brace header form with `attr_list` enabled in order to generate appropriate, compatible HTML with the chosen JavaScript highlighter.
- **NEW**: SuperFences: backwards incompatible changes where made to custom fence API. See [Release Notes](./releases/8.0.md8.0) for instructions on how to migrate to the new API. Some temporary support for most of the old format is in place, but is deprecated.
- **NEW**: SuperFences: has removed legacy code tab feature. Associated `legacy_tab_classes` option has been removed. Please use the Tabbed extension to create general purpose tabs for code blocks or other content.
- **NEW**: Highlight: add new option `language_prefix` which controls the prefix applied to language classes when Pygments is not being used.
- **NEW**: Highlight: A new option called `code_attr_on_pre` was added to the Highlight extension and controls whether language classes, and any ids, attributes, and classes that are defined in fenced code attribute list style headers, are attached to the code element or pre element. This has effect when using Pygments.
- **NEW**: Highlight: option `linenums` now defaults to `None` and accepts `None`, `True`, or `False`. `None` is disabled by default, but can be enabled per code block. `True` enables line numbers globally. `False` disables globally and cannot be enabled manually per code block.
- **NEW**: ExtraRawHTML: remove extension.
- **FIX**: Fix issues with complex emphasis combinations in BetterEm.
- **FIX**: Details: fix corner cases related to extension and lists.
- **FIX**: Tabbed: fix corner cases related to extension and lists.
- **FIX**: EscapeAll: Handle HTML entities special.
- **FIX**: SuperFences: Fix parameter unpacking bug.