Use y<C-G> to yank the current object's path

In response to #165.

doc/fugitive.txt

@@ -201,6 +201,16 @@ that are part of Git repositories).
 
 MAPPINGS                                        *fugitive-mappings*
 
+These maps are available everywhere.
+
+                                                *fugitive-c_CTRL-R_CTRL-G*
+<C-R><C-G>              On the command line, recall the path to the current
+                        object (that is, a representation of the object
+                        recognized by |:Gedit|).
+
+                                                *fugitive-y_CTRL-G*
+["x]y<C-G>              Yank the commit SHA and path to the current object.
+
 These maps are available in Git objects.
 
                                                 *fugitive-<CR>*

plugin/fugitive.vim

@@ -139,7 +139,8 @@ function! s:Detect(path)
   endif
   if exists('b:git_dir')
     silent doautocmd User Fugitive
-    cnoremap <expr> <buffer> <C-R><C-G> <SID>recall()
+    cnoremap <buffer> <expr> <C-R><C-G> <SID>recall()
+    nnoremap <buffer> <silent> y<C-G> :call setreg(v:register,<SID>recall())<CR>
     let buffer = fugitive#buffer()
     if expand('%:p') =~# '//'
       call buffer.setvar('&path',s:sub(buffer.getvar('&path'),'^\.%(,|$)',''))