Improve manual section about Info classes

[wilfwilson]

I've tweaked the documentation about Info classes. Mostly these are language adjustments, to make it clearer in my opinion, and to specify that an info level can be any non-negative integer. More seriously, the documentation previously said that InfoWarning is the only class to start with a non-zero info level; but there are several more, and so I have updated the documentation to match the behaviour of GAP.

Note that this addresses some of my confusion mentioned in the discussion on #2809.

[olexandr-konovalov]

Looks good, thanks!

Please remember to check makemanuals in Travis for errors that may be shown in the log without failing the build.

If you want to improve it further, maybe also add that usually info classes are mentioned in the documentation of appropriate functionality; not all of them are documented at the moment, so ??Info may not discover all of them (also something to be improved), but one can try to enter Info and press Tab twice to see their names. Maybe also add an index entry for "verbosity of GAP output", which may be helpful to newcomers looking for such functionality.

[codecov]

Codecov Report

Merging #2834 into master will decrease coverage by 22.17%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master    #2834       +/-   ##
===========================================
- Coverage   76.05%   53.88%   -22.18%     
===========================================
  Files         480      328      -152     
  Lines      241022   165097    -75925     
===========================================
- Hits       183310    88961    -94349     
- Misses      57712    76136    +18424

Impacted Files	Coverage Δ
lib/teachm2.g	0% <0%> (-100%)	⬇️
lib/attr.gi	0% <0%> (-100%)	⬇️
lib/contfrac.gi	0% <0%> (-89.48%)	⬇️
lib/helpt2t.gi	0% <0%> (-83.34%)	⬇️
lib/proto.gi	0% <0%> (-83.34%)	⬇️
lib/ctblauto.gi	0% <0%> (-83.18%)	⬇️
lib/ctbllatt.gi	0% <0%> (-80.72%)	⬇️
lib/teaching.g	3.43% <0%> (-76.17%)	⬇️
lib/algliess.gi	0% <0%> (-75.23%)	⬇️
lib/ctblpope.gi	0% <0%> (-73.86%)	⬇️
... and 370 more

[wilfwilson]

@alex-konovalov I implemented some of your changes: I added an index entry, and I mentioned the lack of documentation and the existence of package info classes.

[fingolfin]

Very nice, thank you!

I actually think this could be mentioned in the release notes, but I guess it's one of those case were you could argue either way?

[olexandr-konovalov]

Looks good, thanks @wilfwilson. I think it's worth to backport to GAP 4.10 (as those info classes that are explicitly mentioned there are all present in GAP 4.10).