Add Mod-Alt-g binding for gotoLine

FIX: Add a keybinding Mod-Alt-g for `gotoLine` to the search keymap,
to make it usable for people whose keyboard layout uses Alt/Option-g
to type some character.

Issue codemirror/dev#1301

src/search.ts

@@ -571,14 +571,15 @@ export const closeSearchPanel: Command = view => {
 ///  - Mod-f: [`openSearchPanel`](#search.openSearchPanel)
 ///  - F3, Mod-g: [`findNext`](#search.findNext)
 ///  - Shift-F3, Shift-Mod-g: [`findPrevious`](#search.findPrevious)
-///  - Alt-g: [`gotoLine`](#search.gotoLine)
+///  - Mod-Alt-g, Alt-g: [`gotoLine`](#search.gotoLine)
 ///  - Mod-d: [`selectNextOccurrence`](#search.selectNextOccurrence)
 export const searchKeymap: readonly KeyBinding[] = [
   {key: "Mod-f", run: openSearchPanel, scope: "editor search-panel"},
   {key: "F3", run: findNext, shift: findPrevious, scope: "editor search-panel", preventDefault: true},
   {key: "Mod-g", run: findNext, shift: findPrevious, scope: "editor search-panel", preventDefault: true},
   {key: "Escape", run: closeSearchPanel, scope: "editor search-panel"},
   {key: "Mod-Shift-l", run: selectSelectionMatches},
+  {key: "Mod-Alt-g", run: gotoLine},
   {key: "Alt-g", run: gotoLine},
   {key: "Mod-d", run: selectNextOccurrence, preventDefault: true},
 ]