Rearrange :Git documentation

Resolves: #2314

Author: tpope

doc/fugitive.txt

@@ -18,6 +18,12 @@ that are part of Git repositories).
                                                 *fugitive-:G*
 :G [args]               Same as :Git, but two characters shorter.
 
+                                                *fugitive-summary*
+:Git                    With no arguments, bring up a summary window vaguely
+                        akin to git-status.  If a summary window is already
+                        open for the current repository, it is focused
+                        instead.  Press g?  or see |fugitive-maps| for usage.
+
                                                 *:Git*
 :Git {args}             Run an arbitrary git command and display any output.
                         On UNIX this uses a pty and on other platforms it uses
@@ -47,12 +53,6 @@ that are part of Git repositories).
 :{range}Git! -p {args}  Run an arbitrary git command, and insert the output
                         after {range} in the current buffer.
 
-                                                *fugitive-summary*
-:Git                    With no arguments, bring up a summary window vaguely
-                        akin to git-status.  If a summary window is already
-                        open for the current repository, it is focused
-                        instead.  Press g?  or see |fugitive-maps| for usage.
-
                                                 *:Git_blame*
 :Git blame [flags]      Run git-blame [flags] on the current file and open the
                         results in a scroll-bound vertical split.  The