Implement virtual space

[x17jiri]

Implementation of virtual space as discussed here: #13960

Examples of this feature:
rec.webm
rec2.webm

Most of the changes fall into one of these categories:

• updated move commands to allow moving the cursor beyond end of line
• code updated to properly handle column numbers beyond the end of line
• CursorPosition.leftoverVisibleColumns replaced with columnHint, which contains the column number that we want to stay in. This makes the calculations easier, but the change needed to be propagated to a few places.

Notable changes in specific files:

• replaceCommand.ts - updated to add spaces when typing beyond end of line
• mouseTarget.ts - updated to generate column for mouse positions beyond end of line
• viewLines.ts - this change was necessary to allow virtual space also on last line of a file
• cursorWordOperations.ts - without this change, Ctrl + Right Arrow (next word) beyond end of line goes to the end of the line instead of the next line

Testing:

• I added a simple unit test but can implement more

[x17jiri]

@microsoft-github-policy-service agree