range-diff(docs): explain how to specify commit ranges

There are three forms, depending whether the user specifies one, two or
three non-option arguments. We've never actually explained how this
works in the manual, so let's explain it.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-range-diff.txt b/Documentation/git-range-diff.txt
index 9701c1e5fdd5a016c360b8102f0193dfa0fb90fb..a968d5237daed52f007958ab78b47a61b2585cfb 100644 (file)
--- a/Documentation/git-range-diff.txt
+++ b/Documentation/git-range-diff.txt
@@ -28,6 +28,17 @@ Finally, the list of matching commits is shown in the order of the
 second commit range, with unmatched commits being inserted just after
 all of their ancestors have been shown.
 
+There are three ways to specify the commit ranges:
+
+- `<range1> <range2>`: Either commit range can be of the form
+  `<base>..<rev>`, `<rev>^!` or `<rev>^-<n>`. See `SPECIFYING RANGES`
+  in linkgit:gitrevisions[7] for more details.
+
+- `<rev1>...<rev2>`. This is equivalent to
+  `<rev2>..<rev1> <rev1>..<rev2>`.
+
+- `<base> <rev1> <rev2>`: This is equivalent to `<base>..<rev1>
+  <base>..<rev2>`.
 
 OPTIONS
 -------