Add Option to Edit Comments Title & Comments Form Title

[samxmunoz]

At present, there are some settings to play with the Comments Title & Comments Form Title - but none to change the wording.

This is something that can be branded (and it would be nice if it was integrated into the comments block instead of having to add a separate Heading or Paragraph block).

I'm thinking this could be added to the sidebar as another option (if Show Post Title is toggled on, you can change the title, for example).

[SH4LIN]

We will be able to modify the comments form title but we might face an issue when accommodating the change for the comments title.

Let's say we provide a way to change the wording of it then how will we accommodate single and multiple comments scenarios?

[SH4LIN]

I have raised PR for updating the comment form title.