Fix selection extend/shrink on JetBrains keymap (#20199)

JetBrains IDE's use `ctrl-w` and `ctrl-shift-w` on Win/Linux and
`cmd-up` and `cmd-down` on mac to extend/shrink selections.

https://www.jetbrains.com/guide/java/tips/extend-selection/

Release Notes:

- Fixed extend/shrink selection on JetBrains keymap

assets/keymaps/linux/jetbrains.json

@@ -25,8 +25,8 @@
       "alt-j": ["editor::SelectNext", { "replace_newest": false }],
       "alt-shift-j": ["editor::SelectPrevious", { "replace_newest": false }],
       "ctrl-/": ["editor::ToggleComments", { "advance_downwards": true }],
-      "alt-up": "editor::SelectLargerSyntaxNode",
-      "alt-down": "editor::SelectSmallerSyntaxNode",
+      "ctrl-w": "editor::SelectLargerSyntaxNode",
+      "ctrl-shift-w": "editor::SelectSmallerSyntaxNode",
       "shift-alt-up": "editor::MoveLineUp",
       "shift-alt-down": "editor::MoveLineDown",
       "ctrl-alt-l": "editor::Format",

assets/keymaps/macos/jetbrains.json

@@ -24,8 +24,8 @@
       "ctrl-g": ["editor::SelectNext", { "replace_newest": false }],
       "ctrl-cmd-g": ["editor::SelectPrevious", { "replace_newest": false }],
       "cmd-/": ["editor::ToggleComments", { "advance_downwards": true }],
-      "alt-up": "editor::SelectLargerSyntaxNode",
-      "alt-down": "editor::SelectSmallerSyntaxNode",
+      "cmd-up": "editor::SelectLargerSyntaxNode",
+      "cmd-down": "editor::SelectSmallerSyntaxNode",
       "shift-alt-up": "editor::MoveLineUp",
       "shift-alt-down": "editor::MoveLineDown",
       "cmd-alt-l": "editor::Format",