ui: documentation fixes

Signed-off-by: Elias Naur <mail@eliasnaur.com>

ui/f32/f32.go

@@ -2,7 +2,7 @@
 
 /*
 Package f32 is a float32 implementation of package image's
-Point and Rectangle
+Point and Rectangle.
 
 The coordinate space has the origin in the top left
 corner with the axes extending right and down.

ui/layout/doc.go

@@ -43,7 +43,7 @@ This example both aligns and insets a child:
 	dims = inset.End(dims)
 
 More complex layouts such as Stack and Flex lay out multiple children,
-but follow the same pattern of constraints and dimensions.
+and stateful layouts such as List accept user input.
 
 */
 package layout

ui/pointer/doc.go

@@ -96,8 +96,8 @@ For multiple grabbing handlers, the foremost handler wins.
 Priorities
 
 Handlers know their position in a matching set of a pointer through
-event priorities. The Shared and Foremost are for matching sets with
-multiple handlers; the Grabbed priority indicate exclusive access.
+event priorities. The Shared and Foremost priorities are for matching sets
+with multiple handlers; the Grabbed priority indicate exclusive access.
 
 Priorities are useful for deferred gesture matching.