Merge branch 'jl/nor-or-nand-and'

Eradicate mistaken use of "nor" (that is, essentially "nor" used
not in "neither A nor B" ;-)) from in-code comments, command output
strings, and documentations.

* jl/nor-or-nand-and:
  code and test: fix misuses of "nor"
  comments: fix misuses of "nor"
  contrib: fix misuses of "nor"
  Documentation: fix misuses of "nor"

diff.c

@@ -3927,7 +3927,7 @@ static int diff_scoreopt_parse(const char *opt)
 		}
 	}
 	if (cmd != 'M' && cmd != 'C' && cmd != 'B')
-		return -1; /* that is not a -M, -C nor -B option */
+		return -1; /* that is not a -M, -C, or -B option */
 
 	opt1 = parse_rename_score(&opt);
 	if (cmd != 'B')