Documentation Guide section is now more structured

[fazpu]

This is an attempt to give the docs a bit more structure so that it is easier to orient around:

visual components

form components

custom clickable components

formatting text and numbers

[lo5]

@fazpu Thanks for the PR.

I like the restructuring you've done, but unfortunately this PR can't be merged because the included files are auto-generated from the guide *.py files using this.

The correct way to perform this kind of restructuring would be to introduce the concept of a hierarchy in the guide files, then modify the generator to handle the hierarchy. Needs some planning/design.