Small doc related to new completion functions

* doc/lispref/minibuf.texi (Programmed Completion):
Mention completion-table-with-cache.

* lisp/minibuffer.el (completion-table-dynamic)
(completion-table-with-cache): Doc fixes.

* etc/NEWS: Related markup.  Unrelated copyedit.

1 files changed, 4 insertions, 2 deletions

diff --git a/etc/NEWS b/etc/NEWS
index b224457b233..5a1863254d4 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1183,15 +1183,17 @@ Either use `completion-all-completions', which returns highlighted
 strings (including for partial or substring completion), or call
 `completion-hilit-commonality' to add the highlight.
 
++++
 *** New function `completion-table-with-cache' is a wrapper for
 `completion-table-dynamic' that caches the result of the last lookup.
 
++++
 *** New function `completion-table-merge' to combine several
 completion tables by merging their completions.
 
 ** New minor modes `prettify-symbols-mode' and `global-prettify-symbols-mode'
-let you enable symbol prettification (replacing a string like "lambda" with
-the Greek lambda character).
+display specified symbols as composed characters.  E.g., in Emacs Lisp mode,
+this replaces the string "lambda" with the Greek lambda character.
 
 ** Terminal changes