refactor(main.c): Simplify 'caseless' toggling

Regarding the note: Control C on most terminals close the
currently running process/program (in this case csope).

We should look to change this bind in the future.

source/main.c

@@ -212,11 +212,9 @@ void linemode_event_loop(void) {
 
 			case 'c': /* toggle caseless mode */
 			case ctrl('C'):
-				if (caseless == false) {
-					caseless = true;
-				} else {
-					caseless = false;
-				}
+				/* 27-11-2024 20:42 yama XXX: The logic works but I am unable
+				to test functionality in the terminal? */
+						  caseless = !(caseless);
                           egrepcaseless(caseless);
                           break;