fix(grid): add alt+l symbol under mac Closes #7287

Author: Aleksandyr

projects/igniteui-angular/src/lib/core/utils.ts

@@ -329,7 +329,9 @@ export const NAVIGATION_KEYS = new Set([
 export const ROW_EXPAND_KEYS = new Set('right down arrowright arrowdown'.split(' '));
 export const ROW_COLLAPSE_KEYS = new Set('left up arrowleft arrowup'.split(' '));
 export const SUPPORTED_KEYS = new Set([...Array.from(NAVIGATION_KEYS), 'enter', 'f2', 'escape', 'esc', 'pagedown', 'pageup', '+', 'add']);
-export const HEADER_KEYS = new Set([...Array.from(NAVIGATION_KEYS), 'escape', 'esc' , 'l']);
+export const HEADER_KEYS = new Set([...Array.from(NAVIGATION_KEYS), 'escape', 'esc' , 'l',
+    /** This symbol corresponds to the Alt + L combination under MAC. */
+    '¬']);
 
 /**
  * @hidden