Restore default value of face completions-common-part

The previous commit titled "Rework face hints for partial-string
completion styles" contained a potentially controversial
backwards-incompatible change to this face's default value.

* lisp/minibuffer.el (completions-common-part): Restore empty
default value.

1 files changed, 6 insertions, 5 deletions

diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index e7d081eaeb2..6a041d1b739 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -1687,11 +1687,12 @@ See also `display-completion-list'.")
   "Face for the first uncommon character in prefix completions.
 See also the face `completions-common-part'.")
 
-(defface completions-common-part '((t (:inherit underline)))
-  "Face for parts of completions matching a pattern.
-You can use it to make the common parts less visible than normal,
-so that the differing parts are emphasized by contrast.  See also
-the face `completions-first-difference'.")
+(defface completions-common-part '((t nil))
+  "Face for the common prefix substring in completions.
+The idea of this face is that you can use it to make the common parts
+less visible than normal, so that the differing parts are emphasized
+by contrast.
+See also the face `completions-first-difference'.")
 
 (defun completion-hilit-commonality (completions prefix-len &optional base-size)
   "Apply font-lock highlighting to a list of completions, COMPLETIONS.