do not use `a' quoting style in comments

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/editors/awk.c b/editors/awk.c
index cc17ad4..372a255 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -230,7 +230,7 @@
  */
 #define	TC_LENGTH	(1 << 20)
 #define	TC_GETLINE	(1 << 21)
-#define	TC_FUNCDECL	(1 << 22)		/* `function' `func' */
+#define	TC_FUNCDECL	(1 << 22)		/* 'function' 'func' */
 #define	TC_BEGIN	(1 << 23)
 #define	TC_END		(1 << 24)
 #define	TC_EOF		(1 << 25)