fix(prettier): Make prettier less spammy when doing format_multirun

[mkanat]

Prettier outputs a ton of messages like this:

AGENTS.md 57ms (unchanged)
README.md 8ms (unchanged)
TODO.md 4ms (unchanged)
defcl/AGENTS.md 2ms (unchanged)
defcl/buf/AGENTS.md 5ms (unchanged)
defcl/buf/README.md 12ms (unchanged)
defcl/proposals/00001-the-define-configuration-language.md 40ms (unchanged)
defcl/proposals/00002-booleans-are-forbidden.md 11ms (unchanged)
defcl/proposals/README.md 1ms (unchanged)
defcl/spec/spec.md 27ms (unchanged)
define/AGENTS.md 8ms (unchanged)
define/compiler/parser_tests/AGENTS.md 2ms (unchanged)

Which are just log noise. It does this because we are passing it explicit filenames. We can turn it off by setting the log level to warning.

Changes are visible to end-users: yes

• Searched for relevant documentation and updated as needed: n/a
• Breaking change (forces users to change their own code or config): no
• Suggested release notes appear below: yes

Made prettier log only warnings by default, to stop spitting out lines like AGENTS.md 57ms (unchanged)

Test plan

It just removes log spam. I ran it locally and it's fine, though I'm not intimately familiar with the rules_lint tests.

[aspect-workflows]

Bazel 7 (Test)

All tests were cache hits

6 tests (100.0%) were fully cached saving 2s.

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Bazel 8 (Test)

All tests were cache hits

6 tests (100.0%) were fully cached saving 2s.

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Bazel 9 (Test)

All tests were cache hits

6 tests (100.0%) were fully cached saving 2s.

[mkanat]

Oh, I see there's a test I need to fix.