Description of the bug

In 1.16.11, if auto_title is set in pymdownx.highlight the added title is not rendered as part of the signature code block. This also breaks the signature code block highlighting.

To Reproduce

set the following in mkdocs.yml

plugins:
  - mkdocstrings:
      handlers:
        python:
          options:
            separate_signature: true

markdown_extensions:
  - pymdownx.highlight:
      auto_title: true

View any generated documentation

Expected behavior

inside div language-python doc-signature highlight, the span containing Python should be class filename, not nf.

Environment information

• System: Linux-5.15.167.4-microsoft-standard-WSL2-x86_64-with-glibc2.35
• Python: cpython 3.10.12 (/usr/bin/python)
• Environment variables:
• Installed packages:
  • mkdocstrings-python v1.16.10

Additional context

Pretty sure this is due to this commit: 7f95686
The regex <span class="[a-z]+"> matches <span class="filename">. You could use <span class="[a-z]{1,2}"> instead potentially?