misc/bash/go: remove "doc" subcommand autocompletion

"go doc" has been removed in CL 17799.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/77420045

misc/bash/go

@@ -20,7 +20,7 @@ _go()
 
   local cmd="${COMP_WORDS[1]}"
 
-  local cmds="build clean env doc fix fmt get
+  local cmds="build clean env fix fmt get
     install list run test tool version vet"
   local addhelp="gopath importpath remote
     testflag testfunc"
@@ -88,9 +88,6 @@ _go()
         COMPREPLY=(`_go_importpath "$cur"`)
       fi
       ;;
-    'doc')
-      COMPREPLY=(`_go_importpath "$cur"`)
-      ;;
     'fix')
       COMPREPLY=(`_go_importpath "$cur"`)
       ;;