admin/render_readmes: Migrate render_pkg_readme() and find_file_by_path() fns to async/await

[eth3lbert]

This PR migrate render_pkg_readme() and find_file_by_path() fns to async/await.

[Turbo87]

is the text_to_html() call fast enough to be performed in an async worker thread? I'm wondering if we should keep it in a spawn_blocking() call

[eth3lbert]

is the text_to_html() call fast enough to be performed in an async worker thread? I'm wondering if we should keep it in a spawn_blocking() call

Good call. I'll answer this question after I experiment with it after I get up :)

[Turbo87]

I also kept it in spawn_blocking() in the corresponding background job for now:

crates.io/src/worker/jobs/readmes.rs

Lines 54 to 62 in 3bfe1cf

	let rendered = spawn_blocking(move || {
	text_to_html(
	&job.text,
	&job.readme_path,
	job.base_url.as_deref(),
	job.pkg_path_in_vcs.as_ref(),
	)
	})
	.await?;

[eth3lbert]

After benchmarking, I believe we need to keep spawn_blocking(). Most markdown files should not take longer than 6ms, but there might be some files that aren't large but still take a lot of time(maybe seconds), which could cause blocking.

[codecov]

Codecov Report

Attention: Patch coverage is 78.00000% with 11 lines in your changes missing coverage. Please review.

Project coverage is 89.47%. Comparing base (b294cee) to head (372f5c0).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
src/bin/crates-admin/render_readmes.rs	78.00%	11 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10070      +/-   ##
==========================================
- Coverage   89.48%   89.47%   -0.01%     
==========================================
  Files         295      295              
  Lines       31260    31271      +11     
==========================================
+ Hits        27973    27980       +7     
- Misses       3287     3291       +4     

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[eth3lbert]

Ah, it seems I didn't commit the modified part correctly for some reason.
I've rebased to the latest main and made slight modifications to align with our recent work.