patch 9.0.0828: various typos

Problem:    Various typos.
Solution:   Correct typos. (closes #11432)
diff --git a/src/message_test.c b/src/message_test.c
index 6f71aff..21ec4db 100644
--- a/src/message_test.c
+++ b/src/message_test.c
@@ -154,7 +154,7 @@
 /*
  * Test vim_snprintf() with a focus on checking that truncation is
  * correct when buffer is small, since it cannot be tested from
- * vim scrip tests. Check that:
+ * vim script tests. Check that:
  * - no buffer overflows happens (with valgrind or asan)
  * - output string is always NUL terminated.
  *