Merge branch 'jc/blame-follows-renames' into maint

It was unclear in the documentation for "git blame" that it is
unnecessary for users to use the "--follow" option.

* jc/blame-follows-renames:
  git blame: document that it always follows origin across whole-file renames

Author: gitster

Documentation/git-blame.txt

@@ -20,6 +20,12 @@ last modified the line. Optionally, start annotating from the given revision.
 
 The command can also limit the range of lines annotated.
 
+The origin of lines is automatically followed across whole-file
+renames (currently there is no option to turn the rename-following
+off). To follow lines moved from one file to another, or to follow
+lines that were copied and pasted from another file, etc., see the
+`-C` and `-M` options.
+
 The report does not tell you anything about lines which have been deleted or
 replaced; you need to use a tool such as 'git diff' or the "pickaxe"
 interface briefly mentioned in the following paragraph.