Pymdown-extensions

- **FIX**: Blocks: An empty, raw block type should not cause an error.

- **FIX**: Blocks: Fix some corner cases with `md_in_html`.

- **FIX**: MagicLink: Ensure that repo names that start with `.` are handled correctly.
- **FIX**: FancyLists: Fix case were lists could be falsely created when a line started with `.` or `)`.

- **NEW**: Blocks.HTML: Add new `custom` option to specify tags and the assumed handling for them when automatic mode
is assumed. This can also be used to override the handling for recognized tags with automatic handling.
- **FIX**: Fix tests to pass with Pygments 2.19+.

- **NEW**: Snippets: Allow multiple line numbers or line number blocks separated by `,`.
- **NEW**: Snippets: Allow using a negative index for number start indexes and end indexes. Negative indexes are converted to positive indexes based on the number of lines in the snippet.
- **FIX**: Snippets: Properly capture empty newline at end of file.
- **FIX**: Snippets: Fix issue where when non sections of files are included, section labels are not stripped.
- **FIX**: BetterEm: Fixes for complex cases.
- **FIX**: Blocks: More consistent handling of empty newlines in block processor extensions.

- **NEW**: Blocks: Blocks extensions no longer considered in beta.
- **NEW**: Details: Details is marked as "legacy" in documentation in favor of the new `pymdownx.blocks.details` approach.
- **NEW**: Tabbed: Tabbed is marked as "legacy" in documentation in favor of the new `pymdownx.blocks.tab` approach.
- **NEW**: Caption: Add new "blocks" style extension called Caption which helps with specifying figures with captions.
- **NEW**: Emoji: Add a new `strict` option that will raise an exception if an emoji is used whose name has changed,
removed, or never existed.
- **FIX**: Emoji: Emoji links should be generated such that they point to the new CDN version.