Allow disabling linkcheck anchor checks for specific URLs

[yukiisbored]

Is your feature request related to a problem? Please describe.
It appears GitHub has made the Markdown renderer/file viewer require JavaScript which breaks linkcheck anchor checks.

Describe the solution you'd like

A config which disables the linkcheck anchors check based on a regex of the entire URL would allow for cases like these to be handled while still validating whether the page itself exists and keep anchor checks enabled for others.

linkcheck_anchors_disabled = [
   # Requires JavaScript
   r'https://github.com'
]

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context

This is what the page looks like without JavaScript enabled:

• Related issue: Sphinx anchor linkcheck fails for GitHub links to Markdown files NixOS/nix.dev#631

[picnixz]

@yukiisbored Just to be clear, if the url is

• https://github.com/org/repo#anchor, or
• https://github.com/org/repo/blob/main/file.ext#anchor,

you want linkcheck to only check that https://github.com/org/repo and https://github.com/org/repo/blob/main/file.ext exist without checking the anchors in the README or in file.ext respectively ?

[yukiisbored]

@picnixz yup, that is correct.