Remove browse-kill-ring-highlight-inserted-item-style.

Restore browse-kill-ring-highlight-inserted-item, and allow it to take
value `pulse' and `solid' as well as `nil' and `t'.  The value `t' means
default, which is currently `pulse', `nil' still means off.

ChangeLog:

	Remove `browse-kill-ring-highlight-inserted-item-style' and
	instead allow `browse-kill-ring-highlight-inserted-item' to take
	the value `pulse' or `solid' as well as `nil' and `t'.  It's type
	is changed to `choice' accordingly.  The value `t' now means use
	the default highlight style, which is currently `pulse', `nil'
	still means turn off highlighting of inserted items.