Add altClickForMouseEvents option for issue #5952

When enabled during mouse events mode, click/drag/move events require the alt
key while wheel events are unaffected. Selection stays enabled by default
and takes precedence over macOptionClickForcesSelection.

Co-authored-by: Daniel Imms <Tyriar@users.noreply.github.com>

src/common/services/OptionsService.ts

@@ -52,6 +52,7 @@ export const DEFAULT_OPTIONS: Readonly<Required<ITerminalOptions>> = {
   windowOptions: {},
   windowsPty: {},
   wordSeparator: ' ()[]{}\',"`',
+  altClickForMouseEvents: false,
   altClickMovesCursor: true,
   convertEol: false,
   termName: 'xterm',

src/common/services/Services.ts

@@ -209,6 +209,7 @@ export type LogLevel = 'trace' | 'debug' | 'info' | 'warn' | 'error' | 'off';
 export interface ITerminalOptions {
   allowProposedApi?: boolean;
   allowTransparency?: boolean;
+  altClickForMouseEvents?: boolean;
   altClickMovesCursor?: boolean;
   cols?: number;
   convertEol?: boolean;