Refine copy of Supported Templates section in admin screen

[amedina]

• Both sections heading must be bold
• Make first-column heading concise: Content types available as AMP
• In second column, make the Singular template non-selectable when it is required by other templates (e.g. Posts)
• Remove notice Required...

[westonruter]

• Both sections heading must be bold

Fixed in 32b1dd1

[westonruter]

• Remove notice Required...

Fixed in 9105286

[westonruter]

• Both sections heading must be bold
• Make first-column heading concise: Content types available as AMP

What appears here is actually not intended to be a heading. It's a description. The heading got hidden accidentally. Now it appears as:

When in legacy mode, the heading is hidden since only the post types are shown in the first place:

[westonruter]

• In second column, make the Singular template non-selectable when it is required by other templates (e.g. Posts)

How about this as an alternative: When unchecking the Singular template, throw up a confirm() dialog:

Done in 0a6df8c.

[amedina]

Love those changes. Very much aligned with the rest of the UI.

[westonruter]

One other thing I noticed missing is a description paragraph to go under the Templates heading. So in 1084e18 I've added a paragraph that has a link to the template hierarchy handbook page:

[amedina]

Oh yes; that is needed.

The copy: Serve all templates as AMP regardless of what is being queried can be calibrated as well. We will do that on the copy overall pass.