Move fontawesome icons check at compile-time

[GuillaumeGomez]

Now, we have the list of icons we use with their "variant(s)" (ie Brands, Regular or Solid) represented by a trait. To render as one of the variant, the corresponding method needs to be called.

[syphar]

I really like what's possible with rinja & rust with a deeper integration between rust & the template.

Generally:

• I think the compiled icon classes should be inside font-awesome-as-a-crate (perhaps behind a feature), and shouldn't have to be manually added. So all the icons can be added with the build script?
• nit: I feel like accessing the icons in the templates shouldn't be via filters:: but something like icons::

[GuillaumeGomez]

The icons structs are now generated in the sub-crate directly. Since there is no int into having the render_* method I originally added, I instead kept the filters and simply updated them. Code still got simplified and the checks are now at compile-time. :)

[syphar]

last question I think, thank you!

Generally I think before we create a release for the font-awesome crate we should add some documentation around the types (and for that matter, the old method to output the SVG). But we can do that separately.

[GuillaumeGomez]

Updated!

[GuillaumeGomez]

Removed serde impl on GlobalAlert and simplified the field to a specific icon.

[GuillaumeGomez]

Gonna send a follow-up for the doc for the fontawesome crate.