HTML head customisation with head.hbs

[GillesRasigade]

Allow to define custom attributes within the HTML tag thanks to a head.hbs template file.

A typical use case is the addition of mobile capabilities for PWA deployment for example to render the doc in fullscreen once added to the home screen (Android or iOS):

<meta name="apple-mobile-web-app-capable" content="yes" />
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="mobile-web-app-capable" content="yes">

[ehuss]

Could you also update the documentation in the theme docs for this and header.hbs?

[ehuss]

I'm not sure why this is added.

[GillesRasigade]

I added this to avoid having a error after executing clippy:

[ehuss]

Ah, I see. I just pushed a change to rewrite it: #1214. I usually prefer unrelated changes like this to be separate.

[ehuss]

I'd prefer to avoid unrelated formatting changes. Can you remove all the whitespace changes and formatting changes?

[GillesRasigade]

Code auto-formatting has been reverted.

[ehuss]

@Dylan-DPC does this seem like a reasonable idea to you? I suspect there might be some longer term issues with making it easier to extend the templates (#353 ?), but this seems like a simple, incremental improvement.

[Dylan-DPC-zz]

i don't see any issue with this

[GillesRasigade]

Documentation added. Comments answered. Thanks for your reviews.

[ehuss]

Thanks!

[code-ink-space]

The documentation might be confusing.
https://rust-lang.github.io/mdBook/format/theme/index.html

It says:

The theme is totally customizable, you can selectively replace every file from the theme by your own by adding a theme directory next to src folder in your project root.

I think it should say "under" or "inside" the src folder because that's what worked for me. Not having theme next to src but inside it.
Doing mdbook init --theme made me see the correct directory structure.