patch 9.1.0259: Normal mode TextChanged isn't tested properly

Problem:  Normal mode TextChanged isn't tested properly.
Solution: Combine Test_Changed_ChangedI() and Test_Changed_ChangedI_2()
          and also run it on Windows. Fix a typo in main.c.
          (zeertzjq)

closes: #14396

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/main.c

@@ -1098,7 +1098,7 @@ is_safe_now(void)
 }
 
 /*
- * Trigger SafeState if currently in s safe state, that is "safe" is TRUE and
+ * Trigger SafeState if currently in a safe state, that is "safe" is TRUE and
  * there is no typeahead.
  */
     void