[Merged by Bors] - chore: rename the commandStart linter to whitespace

[grunweg]

The linter was always essentially checking all kinds of whitespace issues,
so the new name is equally descriptive already.
A future PR will extend the linter to all proof bodies; then this name would
have been actively misleading.

---

[github-actions]

PR summary cb3ccde1ed

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff

+ whitespaceLinter
- commandStartLinter

You can run this locally as follows

## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>

The doc-module for script/declarations_diff.sh contains some details about this script.

---

No changes to technical debt.

You can run this locally as

./scripts/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

---

note: file MathlibTest/CommandStart.lean` was renamed to `MathlibTest/WhitespaceLinter.lean without a module deprecation
Please create a follow-up pull request adding one. Thanks!

note: file Mathlib/Tactic/Linter/CommandStart.lean` was renamed to `Mathlib/Tactic/Linter/Whitespace.lean without a module deprecation
Please create a follow-up pull request adding one. Thanks!

[Vierkantor]

LGTM otherwise. I checked that all changes outside of the file defining this linter replace "commandstart" with "whitespace" (case insensitive).

[Vierkantor]

bors d+

[mathlib-bors]

✌️ grunweg can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

[grunweg]

Thanks for the quick review!

[leanprover-community-mathlib4-bot]

As this PR is labelled auto-merge-after-CI, we are now sending it to bors:

bors merge

[mathlib-bors]

Canceled.

[grunweg]

bors merge

[mathlib-bors]

Build failed:

• Post-Build Step

[grunweg]

With the latest change, the test fails: deprecating the option only lints upon uses of it in code, but not inside set_option calls. Luckily, we have a linter for that, which I added a case to. I'd prefer a quick re-review: I don't consider this controversial at all, but this is a larger decision than most of this PR.

[adomani]

Thanks! 🐙

Having the deprecation will help with the automatic removal later on and the setOption linter emitting a warning is a great use of the available tools!

bors d+

[mathlib-bors]

✌️ grunweg can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

[grunweg]

Thanks for the fast review!
bors merge

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

• Build
• Lint style
• Post-Build Step