patch 9.1.1319: Various typos in the code, issue with test_inst_complete.vim

Problem:  Various typos in the code, redundant and strange use of
          :execute in test_ins_complete.vim (after 9.1.1315).
Solution: Fix typos in the code and in the documentation, use the
          executed command directly (zeertzjq).

closes: #17143

Co-authored-by: Christ van Willegen <cvwillegen@gmail.com>
Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/normal.c b/src/normal.c
index 6cd9004..ea30607 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -2786,7 +2786,7 @@
 		}
 		break;
 
-		// "zp", "zP" in block mode put without addind trailing spaces
+		// "zp", "zP" in block mode put without adding trailing spaces
     case 'P':
     case 'p':  nv_put(cap);
 	       break;