[PATCH/RFC 04/12] docs: use <sha1> to mean unabbreviated ID

[Mark Lodato <lodatom@gmail.com>]

There are some places that literally require a full, 40-character SHA-1
ID, rather than a generic revision specifier.  Introduce in git(1) the
<sha1> terminology to mean this.  Use <sha1> in git-diff-tree(1) to note
that --stdin only takes <sha1>'s, not generic <tree>'s or <commit>'s.

Signed-off-by: Mark Lodato <lodatom@gmail.com>
---
 Documentation/git-diff-tree.txt |    4 ++--
 Documentation/git.txt           |    5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-diff-tree.txt b/Documentation/git-diff-tree.txt
index a7e37b8..5d0310b 100644
--- a/Documentation/git-diff-tree.txt
+++ b/Documentation/git-diff-tree.txt
@@ -49,8 +49,8 @@ include::diff-options.txt[]
 --stdin::
 	When '--stdin' is specified, the command does not take
 	<tree-ish> arguments from the command line.  Instead, it
-	reads lines containing either two <tree>, one <commit>, or a
-	list of <commit> from its standard input.  (Use a single space
+	reads lines containing <sha1>'s: either two trees, one commit, or
+	multiple commits from its standard input.  (Use a single space
 	as separator.)
 +
 When two trees are given, it compares the first tree with the second.
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 35c0c79..a635281 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -412,6 +412,11 @@ list.
 
 Identifier Terminology
 ----------------------
+<sha1>::
+	Indicates a full, 40-character SHA-1 identifier of an object.
+	The type of the referenced object is unspecified.
+	Abbreviated or symbolic identifiers cannot be used.
+
 <object>::
 	Indicates the object name for any type of object.
 
-- 
1.7.0.2