vim: Add Separator and RemoveIndent in Join Lines, fix gJ use space join (#22496)

Closes #22492

Release Notes:

- Added Join Lines Separator And RemoveIndent

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

assets/keymaps/vim.json

@@ -197,6 +197,7 @@
       "d": ["vim::PushOperator", "Delete"],
       "shift-d": "vim::DeleteToEndOfLine",
       "shift-j": "vim::JoinLines",
+      "g shift-j": "vim::JoinLinesNoWhitespace",
       "y": ["vim::PushOperator", "Yank"],
       "shift-y": "vim::YankLine",
       "i": "vim::InsertBefore",
@@ -278,6 +279,7 @@
       "g shift-i": "vim::VisualInsertFirstNonWhiteSpace",
       "g shift-a": "vim::VisualInsertEndOfLine",
       "shift-j": "vim::JoinLines",
+      "g shift-j": "vim::JoinLinesNoWhitespace",
       "r": ["vim::PushOperator", "Replace"],
       "ctrl-c": ["vim::SwitchMode", "Normal"],
       "escape": ["vim::SwitchMode", "Normal"],