Clean up 'What's new in Qt 6.5'

Clean up What's new in Qt 6.5 documentation page:

New and Restored Modules section

• Add links to new modules (Qt Location, Qt Grpc).
  • Does Qt Quick Effect Maker have documentation? If not, maybe link to blog post?
• Document more clearly which modules are new, and which moved out of TP state

New Features

• Remove 'Nothing to see here' placeholders (after double checking with https://codereview.qt-project.org/q/topic:api-change-review-6.5 and New Classes and Functions in Qt 6.5 that there are indeed no relevant API changes worthwhile to mention)
• General grammar cleanup