Mark `keep-lines', `flush-lines' and `how-many' as documented in the manual.

Mark C-down-mouse-3 as documented.

etc/NEWS

@@ -39,6 +39,7 @@ maximum buffer size.  See etc/MACHINES for instructions.
 ** The new global minor mode `auto-image-file-mode' allows image files
 to be visited as images.
 
++++
 ** The functions `keep-lines', `flush-lines' and `how-many' now
 operate on the active region in Transient Mark mode.
 
@@ -157,6 +158,7 @@ interpreted by the interpreter matched by the second group of the
 regular expression.  The mode is then determined as the mode
 associated with that interpreter in `interpreter-mode-alist'.
 
++++
 ** C-down-mouse-3 is bound differently.  Now if the menu bar is not
 displayed it pops up a menu containing the items which would be on the
 menu bar.  If the menu bar is displayed, it pops up the major mode