Add do_action hooks when rendering templates and template parts. ( #32309 )

[bobbingwide]

Description

I've added some calls to do_action() for two new action hooks: rendering_template and rendering_template_part.
These allow plugins / themes to develop extensions that will enable problem determination and/or logic associated with invocation context.
For example, I use these hooks to implement a debug block that will indicate which template has been used, the start and end of a template part and other information relevant during problem determination. See bobbingwide/sb-debug-block#2

How has this been tested?

I tested the changes by applying the rendering_template hook to Gutenberg v10.7.2 build, and the rendering_template_part hook to an override of render_core_block_template_part in my ThisIs theme.

Unfortunately I couldn't test using the latest extract from Gutenberg trunk since I could not get the build to work. Both npm run dev and npm run build fail. See bobbingwide/sb-debug-block#3

Screenshots

Types of changes

Implements Feature Request #32309

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• I've tested my changes with keyboard and screen readers.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR (please manually search all *.native.js files for terms that need renaming or removal).