Offer canonical non changing links to always current documentation

[jidanni]

Let's say we were reading

​file:///usr/share/doc/grass-doc/html/d.erase.html

offline.

Well wouldn't it be great if within it there was a link to

https://grass.osgeo.org/grass79/manuals/d.erase.html

Such a link could have many uses: Let's say we were composing a email offline, and wanted to refer to that page, but didn't want to go online just yet to check the URL.

Or let's say we were composing a bug report offline, and wanted to make sure it was useful when later posted online.

In fact, instead of

https://grass.osgeo.org/grass79/manuals/d.erase.html

how about just

https://grass.osgeo.org/grass/manuals/d.erase.html

and hyperlink it as "Permalink to this [d.erase, etc.] man page".

Yes, grass.osgeo.org needs to offer permalinks to these documentation items. OK, call them canonical links or something.

You see users are tearing their hair out wanting to simply tell their friends about a certain man page, without having to worry that it will gradually get stale, and finally disappear.

Sure, if they really want to link to a certain version of a man page, for use in a court of law, then they can still use the current numbered

[jidanni]

So /grass/ could always point to "current". and /grass-dev/ could always point to the pending next release, etc.

As far as the exact names, I only briefly thought of them. So maybe call it something else than /grass-dev/.