[PATCH v2] Add reference for status letters in documentation.

[Yann Dirson <ydirson@altern.org>]

Also fix error in diff_filepair::status documentation, and point to
the in-code reference as well as the doc.

Signed-off-by: Yann Dirson <ydirson@altern.org>
---

Since diffcore.h is for devs anyway, it is IMHO a good idea to let it
also point to the in-code doc.

 Documentation/diff-format.txt |   16 ++++++++++++++++
 diffcore.h                    |    2 +-
 2 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/Documentation/diff-format.txt b/Documentation/diff-format.txt
index 400cbb3..aafd3a3 100644
--- a/Documentation/diff-format.txt
+++ b/Documentation/diff-format.txt
@@ -46,6 +46,22 @@ That is, from the left to the right:
 . path for "dst"; only exists for C or R.
 . an LF or a NUL when '-z' option is used, to terminate the record.
 
+Possible status letters are:
+
+- A: addition of a file
+- C: copy of a file into a new one
+- D: deletion of a file
+- M: modification of the contents or mode of a file
+- R: renaming of a file
+- T: change in the type of the file
+- U: file is unmerged (you must complete the merge before it can
+be committed)
+- X: "unknown" change type (most probably a bug, please report it)
+
+Status letters C and M are always followed by a score (denoting the
+percentage of similarity between the source and target of the move or
+copy), and are the only ones to be so.
+
 <sha1> is shown as all 0's if a file is new on the filesystem
 and it is out of sync with the index.
 
diff --git a/diffcore.h b/diffcore.h
index 713cca7..5b63458 100644
--- a/diffcore.h
+++ b/diffcore.h
@@ -62,7 +62,7 @@ struct diff_filepair {
 	struct diff_filespec *one;
 	struct diff_filespec *two;
 	unsigned short int score;
-	char status; /* M C R N D U (see Documentation/diff-format.txt) */
+	char status; /* M C R A D U etc. (see Documentation/diff-format.txt or DIFF_STATUS_* in diff.h) */
 	unsigned broken_pair : 1;
 	unsigned renamed_pair : 1;
 	unsigned is_unmerged : 1;