test: add highlighted outputs for Tcl shebang regression tests

Generate highlighted test outputs for tclsh, wish, and expect
shebang detection files to prevent regressions.

tests/integration_tests.rs

@@ -4201,6 +4201,8 @@ fn plain_without_diff_still_works() {
         .assert()
         .success()
         .stdout("line 1\nline 2 modified\nline 3\nline 4 added\n");
+}
+
 #[test]
 fn tcl_shebang_detection_tclsh() {
     bat()