Revert link accent styling in file table

[pointydev]

Describe the change you'd like I think primary and secondary file links should be a different shade/the default colour, as using the accent colour can look extremely overwhelming at a cursory glance.

Additional context See this comment thread on the offending commit: https://github.com/StylishThemes/GitHub-Dark/commit/22740553b2c7c9a90c4919d0b7957fa24e171e9a#r58142290. @srichter also kindly made a snippet to revert this, however I don't think a theme with this level of customisation should have to resort to snippets like this.

@Geeyun-JY3 also highlighted the following point, which provides a rationale behind reverting it other than "it looks better":

And if commit message contains # and issue or pull request number, it would make users overlook the short link.

Thanks, Elliott