Fix spelling/wording issues

Found by using:
    codespell --builtin clear,rare,usage,informal,code,names

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

README.md

@@ -6,7 +6,7 @@ Xorg mailing list:
 
   https://lists.x.org/mailman/listinfo/xorg
 
-The master development code repository can be found at:
+The primary development code repository can be found at:
 
   https://gitlab.freedesktop.org/xorg/app/listres
 

listres.c

@@ -124,7 +124,7 @@ static void tree_known_widgets (void)
 
 
 /*
- * print_classname - print out the superclass-to-subclass hierchy of names
+ * print_classname - print out the superclass-to-subclass hierarchy of names
  * in the form super\sub\sub....
  */
 static int print_classname (XmuWidgetNode *node, XmuWidgetNode *topnode,