Merge branch 'ma/doc-git-version' into maint

Doc update.

* ma/doc-git-version:
  documentation: add documentation for 'git version'

Documentation/git-version.txt

@@ -0,0 +1,28 @@
+git-version(1)
+==============
+
+NAME
+----
+git-version - Display version information about Git
+
+SYNOPSIS
+--------
+[verse]
+'git version' [--build-options]
+
+DESCRIPTION
+-----------
+With no options given, the version of 'git' is printed on the standard output.
+
+Note that `git --version` is identical to `git version` because the
+former is internally converted into the latter.
+
+OPTIONS
+-------
+--build-options::
+	Include additional information about how git was built for diagnostic
+	purposes.
+
+GIT
+---
+Part of the linkgit:git[1] suite

Documentation/git.txt

@@ -41,6 +41,10 @@ OPTIONS
 -------
 --version::
 	Prints the Git suite version that the 'git' program came from.
++
+This option is internaly converted to `git version ...` and accepts
+the same options as the linkgit:git-version[1] command. If `--help` is
+also given, it takes precedence over `--version`.
 
 --help::
 	Prints the synopsis and a list of the most commonly used