notes: fix core.notesRef documentation

The path format was inconsistent with the one used in git-notes.sh: it
supposedly split the sha1 in the same 2/38 format that .git/objects
uses, but the code uses the full sha1 without a path separator.

While at it, also fix a grammatical error.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -424,15 +424,13 @@ overlapping IO's.
 
 core.notesRef::
 	When showing commit messages, also show notes which are stored in
-	the given ref.  This ref is expected to contain paths of the form
+	the given ref.  This ref is expected to contain files named
-	??/*, where the directory name consists of the first two
+	after the full SHA-1 of the commit they annotate.
-	characters of the commit name, and the base name consists of
-	the remaining 38 characters.
 +
-If such a path exists in the given ref, the referenced blob is read, and
+If such a file exists in the given ref, the referenced blob is read, and
 appended to the commit message, separated by a "Notes:" line.  If the
 given ref itself does not exist, it is not an error, but means that no
-notes should be print.
+notes should be printed.
 +
 This setting defaults to "refs/notes/commits", and can be overridden by
 the `GIT_NOTES_REF` environment variable.