Add vim::MoveTo{Next,Prev} flags for regex and case sensitive search (#18429)
This makes the hard-coded regex and case-sensitive search flags in
`vim::MoveToNext` and `vim::MoveToPrev` commands configurable in key
bindings.
Example:
```json
{
"context": "VimControl && !menu",
"bindings": {
"*": ["vim::MoveToNext", { "regex": false, "caseSensitive": false }],
"#": ["vim::MoveToPrev", { "regex": false, "caseSensitive": false }]
}
}
```
Closes #15837.
Release Notes:
- Added `regex` and `caseSensitive` arguments to `vim::MoveToNext` and
`vim ::MoveToPrev` commands, for toggling regex and case sensitive
search.