bug#51444: One issue in NEWS

[Juri Linkov <juri@linkov.net>]

Currently I'm reading NEWS.28 and noticed this section marked by
+++ as documented in the manual:

  +++
  ** New user option 'next-error-message-highlight'.
  In addition to a fringe arrow, 'next-error' error may now optionally
  highlight the current error message in the 'next-error' buffer.
  This user option can be also customized to keep highlighting on all
  visited errors, so you can have an overview what errors were already visited.

But the source of the manual has only these two lines:

  @findex next-error-message
  @vindex next-error-message-highlight

'next-error-message' is a face and can be removed from the index.
But 'next-error-message-highlight' is a user option, and when
the reader selects it from the Info index, its page says nothing
about this option.  This patch fills the gap:

diff --git a/doc/emacs/building.texi b/doc/emacs/building.texi
index 8de93867ba..2c694a5e39 100644
--- a/doc/emacs/building.texi
+++ b/doc/emacs/building.texi
@@ -213,7 +213,6 @@ Compilation Mode
 @kindex M-g n
 @kindex C-x `
 @findex next-error
-@findex next-error-message
 @vindex next-error-message-highlight
 @vindex next-error-highlight
 @vindex next-error-highlight-no-select
@@ -263,7 +262,9 @@ Compilation Mode
 highlights the relevant source line.  The duration of this highlight
 is determined by the variable @code{next-error-highlight} for the locus
 in the selected buffer, and @code{next-error-highlight-no-select} for
-the locus in non-selected buffers.
+the locus in non-selected buffers.  Also you can customize the variable
+@code{next-error-message-highlight} that defines how to highlight the
+current error message in the buffer that contains messages.
 
 @vindex compilation-context-lines
   If the @file{*compilation*} buffer is shown in a window with a left
--