Documentation/git-status: clarify status table for porcelain mode

It is possible to have the output ' A' from 'git status --porcelain'
by adding a file using the '--intend-to-add' flag.  Make this clear by
adding the pattern in the table of the documentation.

However the mode 'DM' (deleted in the index, modified in the working tree)
is not possible in the non-merge case in which the file only shows
as 'D ' (and adding it back to the worktree would show an additional line
of an '??' untracked file). It is also not possible in the merge case as
then the mode involves a 'U' on one side of the merge.
Remove that pattern.

Reported-by: Ross Light <light@google.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-status.txt

@@ -156,10 +156,10 @@ in which case `XY` are `!!`.
 
     X          Y     Meaning
     -------------------------------------------------
-              [MD]   not updated
+	     [AMD]   not updated
     M        [ MD]   updated in index
     A        [ MD]   added to index
-    D         [ M]   deleted from index
+    D                deleted from index
     R        [ MD]   renamed in index
     C        [ MD]   copied in index
     [MARC]           index and work tree matches