patch 8.1.0989: various small code ugliness

Problem:    Various small code ugliness.
Solution:   Remove pointless NULL checks. Fix function calls. Fix typos.
            (Dominique Pelle, closes #4060)

src/version.c

@@ -41,7 +41,7 @@ init_longVersion(void)
 {
     /*
      * Construct the long version string.  Necessary because
-     * VAX C can't catenate strings in the preprocessor.
+     * VAX C can't concatenate strings in the preprocessor.
      */
     strcpy(longVersion, VIM_VERSION_LONG_DATE);
     strcat(longVersion, __DATE__);
@@ -779,6 +779,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    989,
 /**/
     988,
 /**/