Revert creation of Doc Menu, move back to Help menu (#15762)
Fixes #15749
Partially reverts #15688
Summary of the issue:
There has been significant negative feedback to the creation of the documentation menu.
Instead items should be return to the help menu.
Given that there is now 11 items in the Help menu, more separators should be added.
Description of user facing changes
The new help menu structure is:
User Guide
Key commands
Changes
[separator]
NV Access website
NV Access Get Help page
NV Access Shop page
[separator]
License
Contributors
[separator]
Welcome dialog
Check for update
About dialog
Description of development approach
Move items back, remove internal variable menu_help which duplicated self.helpMenu
