Error message to be improved when trying to submit an empty review

[Hareesh Pillai]

On the Themes and Plugins page, when an empty review without title or content is submitted, an error message is displayed (as expected).

However, the copy can be improved for these messages.

Present:

Error: Your topic needs a title.
Error: Your topic cannot be empty.

Proposed:

Error: Your review needs a title.
Error: Your review cannot be empty.

Link to theme review: ​https://wordpress.org/support/theme/twentytwenty/reviews/#new-post
Link to plugin review: ​https://wordpress.org/support/plugin/akismet/reviews/#new-post

[dd32]

In 11382:

Support Forums: Update two errors on the review form to reference review rather than topic.

Fixes #5295.