Instead of documenting the new "upgrade" and "downgrade" functions I'd
rather kill this obvious comment.   This also reduce differences with
NetBSD.

Ok?

Index: uvm/uvm_map.h
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_map.h,v
diff -u -p -r1.95 uvm_map.h
--- uvm/uvm_map.h	11 Sep 2025 17:04:35 -0000	1.95
+++ uvm/uvm_map.h	13 Sep 2025 09:54:23 -0000
@@ -376,25 +376,7 @@ int		uvm_map_fill_vmmap(struct vm_map *,
 		    size_t *);
 
 /*
- * VM map locking operations:
- *
- *	These operations perform locking on the data portion of the
- *	map.
- *
- *	vm_map_lock_try: try to lock a map, failing if it is already locked.
- *
- *	vm_map_lock: acquire an exclusive (write) lock on a map.
- *
- *	vm_map_lock_read: acquire a shared (read) lock on a map.
- *
- *	vm_map_unlock: release an exclusive lock on a map.
- *
- *	vm_map_unlock_read: release a shared lock on a map.
- *
- *	vm_map_busy: mark a map as busy.
- *
- *	vm_map_unbusy: clear busy status on a map.
- *
+ * VM map locking operations.
  */
 
 boolean_t	vm_map_lock_try_ln(struct vm_map*, char*, int);