Add tests for missing REM or missing MSG being diagnosed.

src/calendar.c

@@ -1684,7 +1684,7 @@ static void GenerateCalEntries(int col)
 	    /* need to destroy it here. */
 
 	    default:
-                Wprint("Unrecognized command; interpreting as REM MSG ...");
+                Wprint("Unrecognized command; interpreting as REM");
                 CreateParser(CurLine, &p);
 		r=DoCalRem(&p, col);
 		break;

src/main.c

@@ -356,7 +356,7 @@ static void DoReminders(void)
 	    /* If we don't recognize the command, do a REM by default, but warn */
 
 	    default:
-                Wprint("Unrecognized command; interpreting as REM MSG ...");
+                Wprint("Unrecognized command; interpreting as REM");
                 DestroyParser(&p);
                 CreateParser(CurLine, &p);
                 purge_handled = 1;

tests/test.rem

@@ -945,6 +945,9 @@ REM Tue AT 10:00 DURATION [trigtime()] MSG blort
 # Make sure shellescape does not mangle UTF-8 characters
 msg [shellescape("😆")]
 
+This should be diagnosed as implicitly being REM
+REM This should be diganosed as implicitly being MSG-type
+
 # Don't want Remind to queue reminders
 EXIT