bugs with config override logic

[timotheecour]

bugs as of devel 70bd41d
some are pre-existing bugs, other are recent regressions

• regression: --listcmd --hint:link:on --hint:cc:off should show "just the (verbose) link command, but instead it also shows the (verbose) compilation commands
  note: hintLink was recently "broken" in Only print the link command when listCmd is active and fix the docs nim-lang/Nim#13603 and we agreed on proposal 1 to fix it (see Only print the link command when listCmd is active and fix the docs nim-lang/Nim#13603 (comment)); this should work but doesn't yet:

• --verbosity:0 --hint:FOO:on --hint:BAR:of works with every FOO,BAR except for --hint:cc:on

• --hints:off --hint:successx:on does not honor --hint:successx:on but it should because it comes AFTER
  more generally for other hints (eg --hint:conf:on).
  The point of overriding like this is it makes it easy to test 1 thing at a time (whether inside a test where we just want to check 1 aspect, or when you want to debug a specific issue etc)
  It should behave like --verbosity:0 which CAN be overridden (except for --hint:cc:off bug specific to cc)

• --verbosity:0 should imply --hint:processing:off but does not

not sure about these

--verbosity:0 --hint:exec:on works as intended (enables hintExec) but --hint:exec:on --verbosity:0 also enables hintExec even though --verbosity:0 comes after

[Clyybber]

not sure about these

This is intended, and changing it would make the code really messy.

[timotheecour]

after ad6d559 from nim-lang#13606

• --hints:off --hint:cc:on doesn't honor --hint:cc:on
nim c -r -f --skipusercfg --skipparentcfg --hints:off --hint:cc:on $timn_D/src/timn/examples/thello.nim hello world
  (but pre-existing bug)

[timotheecour]

proposal for --hints:on/off (after discussion w @Clyybber)

• current logic is that --hints:on/off acts like a global AND gate on all hints
  this is self-consistant but not very useful, eg it doesn't allow one to override it by simply turning on or off a single hint, or all hints, or all except 1 etc

• proposed logic:
  no separate logic gate, instead it's processed like a command in and processed in regular order:
  --hints:on turns on all hints
  --hints:off turns off all hints
  --hints:off --hint:successx:onends up with onlyhint:successx being on --hints:on --hint:cc:off ends up with all hints on except hint:cc which is off
  --hints:on --hint:cc:off --hints:off` : the obvious thing, all hints are off

• ditto with --warnings:on/off