Feature request: add QuickNav command for Vertical navigation in browse mode #15999

I propose to add Vertical navigation QuickNav command to NVDA. I I will implement this feature request myself if green light is given by NVDA team.

• We define vertical navigation to be jumping to next or previous paragraph, which is vertically aligned visually with the current paragraph, that is their x coordinate is exactly the same.
• This can be useful on websites that visually display data as a table, but for whatever reason NVDA doesn't see the table. This command can be used to navigate to next/previous cell in the same column.
• A good example of this is issues list on github - with this feature users will be able to find the first issue and then navigate between issues in the list using vertical navigation with a single keystroke.
• I propose to assign by default Left bracket [ and Shift+[ gestures to this command.
• This feature has already been implemented in BrowserNav add-on and by default assigned to NVDA+Control+Up/Down gestures.