Support admin render_readme with Cargo.toml without optional readme field

[nipunn1313]

Depends on #3969

(Because of community/community#4477 (comment) - github ends up rendering both diffs together. Go to the commits tab and just look at the most recent commit to review).

https://doc.rust-lang.org/cargo/reference/manifest.html#the-readme-field

[bors]

☔ The latest upstream changes (presumably #3969) made this pull request unmergeable. Please resolve the merge conflicts.

[Turbo87]

Now that I read the docs on this a little more closely I'm wondering how we are handling readme = false, because I guess it wouldn't be able deserialize to Option<String>, right? do we just panic in that case? 😱

[Turbo87]

I've rebased the branch btw :)

[nipunn1313]

yep you're right. There's more to the spec that's not supported. Let me see what I can do.
At the least - this is an improvement (supports more cases than before).

[nipunn1313]

#3971 adds support for out-of-order tar files
That unblocks #3972 which adds support for README.txt and README as well as readme = false
Together they unblock #3973 - which supports relative links in READMEs from non-repo-root packages. Technically it only logically depends on #3971 - but for ease of code rebase I stacked them in this order.

I know there are timezones and whatnot between us, so feel free to update/change these PRs to get as much done as you'd like.

[Turbo87]

@bors r+

[bors]

📌 Commit 824055f has been approved by Turbo87

[bors]

⌛ Testing commit 824055f with merge d9a57fc...

[bors]

💥 Test timed out

[Turbo87]

probably caused by https://www.githubstatus.com/incidents/bdbzpz7qxmbx

@bors retry

[bors]

⌛ Testing commit 824055f with merge 84495e3...

[bors]

☀️ Test successful - checks-actions
Approved by: Turbo87
Pushing 84495e3 to master...