Technically, "-s, --no-patch" is implemented in diff.c ("git diff
--no-patch" is essentially useless, but valid). From the user point of
view, this allows the documentation to show up in "git show --help",
which is one of the most useful use of the option.

While we're there, add a sentence explaining why the option can be
useful.

Signed-off-by: Matthieu Moy <redacted>
---
It might make sense to surround this with ifndef::git-diff[], but
since "git diff --no-patch" actually works, I've left it
unconditional to be technically correct.

 Documentation/diff-options.txt     | 5 +++++
 Documentation/rev-list-options.txt | 4 ----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 87e92d6..bbed2cd 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt

@@ -26,6 +26,11 @@ ifndef::git-format-patch[]
 	{git-diff? This is the default.}
 endif::git-format-patch[]
 
+-s::
+--no-patch::
+	Suppress diff output. Useful for commands like `git show` that
+	show the patch by default, or to cancel the effect of `--patch`.
+
 -U<n>::
 --unified=<n>::
 	Generate diffs with <n> lines of context instead of

diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index c128a85..e632e85 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt

@@ -849,8 +849,4 @@ options may be given. See linkgit:git-diff-files[1] for more options.
 -t::
 
 	Show the tree objects in the diff output. This implies '-r'.
-
--s::
---no-patch::
-	Suppress diff output.
 endif::git-rev-list[]

-- 
1.8.3.1.495.g13f33cf.dirty