Used bold and italic in the markdown to make the stack and heap docum…

[Shiney]

…entation clearer

I could not use colors as suggested for #29854 because Github doesn't support these in markdown, however this solution may be better for color-blind readers.

[rust-highfive]

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

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

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[huonw]

r? @steveklabnik

(I was thinking the colour could be done via <span style="color:..."></span> tags, which the documentation on the website rendered via rustdoc will display, although doing that is clearly much more annoying than bold and italic.)

[steveklabnik]

Ah interesting! I like this idea.

@Shiney , if it isn't too much work, would you mind:

1. adding a sentence or two explicitly mentioning that the names are connected to the styling
2. Squashing this down to one commit

Thank you!

And yes, we could do colors inline. Let's see how this works and maybe do that in the future, depending.

[Shiney]

Okay, I think I've done all the git voodo required to squash the commits to one commit...

[steveklabnik]

You have! Thanks so much.

@bors: r+ rollup

[bors]

📌 Commit 62fa40f has been approved by steveklabnik