Show Page Title placeholder rather than Post Title for page templates

[annezazu]

The Post Title block displays the title for posts, pages, and any other content-type. However, the placeholder only ever shows as "Post Title". This causes folks to sometimes remove it from page templates thinking it doesn't relate to their page title:

page.title.name.mov

In this case, if possible, we should show the block as "page title" in certain contexts, especially since you can currently search for that with the slash inserter:

I couldn't find an open issue for this but if there is one, please feel free to close this out! This issue around preventing removal of important blocks is also related: #40618

[ntsekouras]

I think this could be considered duplicate of #48963.

[annezazu]

Ah ha! Agreed. Thank you. Closing out.