feat(editor): make caret mouse gestures configurable (#2143)

The gesture that adds a caret was hardcoded to Alt+Shift+Click, so it could not be changed in the Keymap settings.

Adds the "Add or Remove Caret" action to Editor Actions, with Alt+Shift+Click as the default in every preset. `multiCaret.ts` now matches the event against that action's effective bindings, so rebinding and removal apply at once. A stroke bound to it takes precedence over Alt-drag column selection and over mouse-shortcut dispatch in the editor; column selection is unchanged otherwise.

Closes #2127
Refs #2126

src/platform/keymaps/intellij-macos.ts

@@ -3,6 +3,7 @@
  * contract between features (which register actions) and keymaps.
  */
 export const intellijMacos: Record<string, string[]> = {
+  "editor.addOrRemoveCaret": ["Alt+Shift+Button1"],
   // Navigate
   "navigate.searchEverywhere": ["Shift Shift"],
   "navigate.gotoClass": ["Meta+O"],

src/platform/keymaps/intellij-windows.ts

@@ -4,6 +4,7 @@
  * there stay unbound here.
  */
 export const intellijWindows: Record<string, string[]> = {
+  "editor.addOrRemoveCaret": ["Alt+Shift+Button1"],
   // Navigate
   "navigate.searchEverywhere": ["Shift Shift"],
   "navigate.gotoClass": ["Ctrl+N"],

src/platform/keymaps/vscode-macos.ts

@@ -4,6 +4,7 @@
  * no binding so switching presets doesn't leak IntelliJ shortcuts.
  */
 export const vscodeMacos: Record<string, string[]> = {
+  "editor.addOrRemoveCaret": ["Alt+Shift+Button1"],
   // Navigate
   "navigate.searchEverywhere": ["Shift Shift"],
   "navigate.gotoClass": [],

src/platform/locales/text/en.json

@@ -1,4 +1,5 @@
 {
+  "Add or Remove Caret": "Add or Remove Caret",
   "Select Python Environment Folder": "Select Python Environment Folder",
   "Checking interpreter": "Checking interpreter",
   "Cannot run this Python interpreter. Select a working Python executable or virtualenv folder.": "Cannot run this Python interpreter. Select a working Python executable or virtualenv folder.",

src/platform/locales/text/zh.json

@@ -193,6 +193,7 @@
   "Clone Caret Below": "在下方添加光标",
   "Join Lines": "合并行",
   "Toggle Case": "切换大小写",
+  "Add or Remove Caret": "添加或移除插入点",
   "Add Carets to Ends of Selected Lines": "在所选行末尾添加光标",
   "Unselect Occurrence": "取消选择匹配项",
   "Paste from History…": "从历史记录粘贴…",