settings: Don't try to disable flake8, document relevant limitation

[projectgus]

Removes flake8 from the list of This plugin will disable [...] by default. This doesn't change the existing behaviour at all:

The flake8 plugin is disabled by default in pylsp. If it's been enabled in the pylsp configuration then it's not actually possible for another plugin like this one to disable it.

The other four plugins disabled by python-lsp-ruff (pycodestyle, pyflakes, mccabe, pyls_isort) are enabled by default so the ruff plugin is able to disable these plugins, provided they're not explicitly enabled in the configuration.

Closes #46

Thanks for maintaining python-lsp-ruff, it's a very handy plugin! 😁

[Shane-XB-Qian]

i am a little confused the title, i remember this 'ruff' plugin was (aim to) going to be the only linter for pylsp,
but now kept the flake8 default be enabled there? if yes, was there some additional configure to disable it?
or some con/pro if leave the 'enable' there? and this seems a bit un-imcompatible (and break game?) if yes.

[jhossbach]

@Shane-XB-Qian Linting with flake8 is disabled by default. The idea behind removing it from the list of disabled plugins was that it would otherwise awake the idea of it always being disabled, regardless of the user configuration.

Effectively this changes nothing since flake8 is disabled by default unless explicitly enabled by the user.

See #46 for more details

[projectgus]

I've edited the description of the PR, as it was a bit terse. Hope that's clearer, @Shane-XB-Qian.

[Shane-XB-Qian]

ok, just wish keep this/its 'aim', make the result be stable and simple/clear.

[Shane-XB-Qian]

except this linter/diag cfg, the left things (to be refined) of pylsp as i knew maybe were:
hover-doc and auto-import, (maybe init/ws configure too), seems they are doing it now.
// but just the latter one was on 'rope' still, wish someday 'ruff' can offer that....... 😄