* src/category.c (Fmodify_category_entry): Document CATEGORY argument.
the current buffer's category table.
CHARACTER can be either a single character or a cons representing the
lower and upper ends of an inclusive character range to modify.
+CATEGORY must be a category name (a character between ` ' and `~').
+Use `describe-categories' to see existing category names.
If optional fourth argument RESET is non-nil,
then delete CATEGORY from the category set instead of adding it. */)
(Lisp_Object character, Lisp_Object category, Lisp_Object table, Lisp_Object reset)