Add strategy to identify Roff man pages: Take 2

[Alhadis]

This PR adds a strategy to identify man-pages with unrecognised file extensions. Added in support of github/markup#1196.

Description

This was previously attempted in #4317, but ditched after the complexity of the PR convinced me a simpler solution was needed to safeguard against incorrectly rendered man-pages. That concern has since been addressed by #4393, leaving us free to adopt a much simpler implementation.

Note that the Manpage strategy deliberately returns two language entries, deferring the exact classification to the heuristics (which determine whether a Roff file should be rendered as a man-page or not).

References: #4258, #4309, #4317

/cc @pchaigno, @lildude, @jordemort, @pali

Checklist:

• I am adding new or changing current functionality
  • I have added or updated the tests for the new or changed functionality.

[stale]

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[jordemort]

pls no close stalebot, I'll try and find a reviewer

[stale]

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[pali]

any update? :-)

[stale]

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[Alhadis]

Nudging @lildude for input.

[lildude]

From a quick look and based on your explanation, it makes sense to me, but I'll let @pchaigno take a peek and comment before making a final decision.

As an aside, you'll need to merge in master to get the tests passing as I fixed the current failure in #4478.

[Alhadis]

Whoops, completely missed that. 😀 Fixed!

[Alhadis]

Nudging @pchaigno.

[stale]

This pull request has been automatically marked as stale because it has not had recent activity, and will be closed if no further activity occurs. If this pull request was overlooked, forgotten, or should remain open for any other reason, please reply here to call attention to it and remove the stale status. Thank you for your contributions.

[Alhadis]

If somebody — anybody — could review this, shut stalebot up, and make many man-page lovers happy, that'd be seriously copacetic.

Seriously.

/cc @pchaigno again

[pchaigno]

I think the current regular expression is going to create issue with other languages (see below). I'm not sure how to best handle this. It's probably better if we avoid hardcoding the problematic extensions...

[Alhadis]

It's probably better if we avoid hardcoding the problematic extensions...

Well, that can always be solved by generating a RegExp from at runtime from every extension which happens to start with a number.

But in any case, this shouldn't be a problem since the manpage-strategy has a lower priority than the filename one does, so "problematic" extensions shouldn't be a problem. 😉

[pchaigno]

LGTM!

[Alhadis]

Merci! 😀

@lildude Alright to merge? ^^

[Alhadis]

/cc'ing @lildude in case he's missed this.

[jordemort]

Yessssssssssss

[Alhadis]

@jordemort Any update on github/markup#1196?