chore(deps): update rust crate handlebars to v4.5.0

[leonzchang]

In the latest version of handlebars, rules for whitespace auto elimination is to check if the directive {{# xxx}}`` and ``{{/ xxx}} is holding a whole line, with leading and trailing whitespaces counted, and then remove the trailing NEWLINE (See template.rs).

{{#options}}
                              <--- this newline will be removed after a standalone block
{{#option "`-o` _outdir_"}}
                              <--- this newline will be removed
Some content

{{/option}}
                              <--- this newline will be removed
{{/options}}
                              <--- this newline will be removed

This PR changes includes (fixes #13162):

1. update handlebars crate to v4.5.0.
2. add extra NEWLINE to helper blocks options, option to align with the new strip rules, preserving the original behavior.
3. update doc(the rest handlebars expression) to align with the new strip rules..

[rustbot]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @ehuss (or someone else) soon.

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[ehuss]

@rustbot author

Please let us know if you have any questions.

[leonzchang]

@rustbot ready

[epage]

Could you update the commits for how you'd want them merged (every commit being "correct")?

[leonzchang]

Could you update the commits for how you'd want them merged (every commit being "correct")?

The example below will break markdown rendering while following the latest version of handlebars strip rules.

 <!-- template -->
{{#options}}

some content...

{{/options}}

### Section options




 <!-- original output -->
<dl>

some content...

</dl>

### Section options 




 <!-- output after update handlebars -->
<dl>
some content...

</dl>
### Section options                             <--- adjacent html and headings breaks markdown rendering

What I have changed is to add an extra newline to preserve the original behavior of the options and option helper blocks. The rest of the expression will follow to the new strip rules, stripping a newline if a block is standalone.

[epage]

To be clear, it looks like your commits in the PR were checkpoints during your development and I suspect they don't all work. I was asking to clean them up, whether thats for squashing all of them into one commit or doing multiple, I leave it to you.

[leonzchang]

To be clear, it looks like your commits in the PR were checkpoints during your development and I suspect they don't all work. I was asking to clean them up, whether thats for squashing all of them into one commit or doing multiple, I leave it to you.

Ok, done.

[epage]

Thanks!

@bors r+

[bors]

📌 Commit b96b244 has been approved by epage

It is now in the queue for this repository.

[bors]

⌛ Testing commit b96b244 with merge c21be2b...

[bors]

☀️ Test successful - checks-actions
Approved by: epage
Pushing c21be2b to master...