nim doc --project: @@ caused issues; use _._ instead

[timotheecour]

we could probably use same mangling for nimcache, it'd look less noisy than current scheme

/cc @kaushalmodi

should fix your comment:

#14448 (comment)

Other options turned out problematic: @@, ..7, 7..

• @@ can cause problems unless it's encoded %40 (ugly) according to https://stackoverflow.com/questions/19509028/can-i-use-an-at-symbol-inside-urls/19737890
• ..7 would show as hidden since starts with .
• 7.. may cause problems on windows see https://docs.microsoft.com/en-us/previous-versions/office/developer/sharepoint-2010/ff407623(v%3Doffice.14) and https://answers.microsoft.com/en-us/msoffice/forum/all/kb3203467-causing-attachments-with-consecutive/4c7d7d34-ced2-4386-85a9-4b093523ba4f
• _. seems perfect; looks like a .. without being too similar to it so there's no confusion... well not sure about hyperlinks that could hide underscores but I guess the dot makes it clear still
• [EDIT] sigh... windows also has problems with _. see https://stackoverflow.com/questions/4075753/how-to-delete-a-folder-that-name-ended-with-a-dot and in fact CI failed for tests/misc/trunner.nim where walkDirRec reported finding _/imp.html instead of _./imp.html => could indicate bug in stdlib for paths ending with dot which are probably legal on windows but oddly supported

only alternative: _

haven't tried but could work; although it's more likely to clash

links for reference

• https://secure.n-able.com/webhelp/NC_9-1-0_SO_en/Content/SA_docs/API_Level_Integration/API_Integration_URLEncoding.html
• https://cwe.mitre.org/data/definitions/32.html
• https://answers.microsoft.com/en-us/msoffice/forum/all/kb3203467-causing-attachments-with-consecutive/4c7d7d34-ced2-4386-85a9-4b093523ba4f
• https://docs.microsoft.com/en-us/previous-versions/office/developer/sharepoint-2010/ff407623(v%3Doffice.14)
• https://stackoverflow.com/questions/27142359/is-a-url-with-multiple-consecutive-dots-valid