Add a note about some raw commands may not work

Wrap them using a Command or function then.

Close #126
Close #133

README.md

@@ -145,9 +145,9 @@ let g:which_key_map['w'] = {
       \ 'l' : ['<C-W>l'     , 'window-right']          ,
       \ 'k' : ['<C-W>k'     , 'window-up']             ,
       \ 'H' : ['<C-W>5<'    , 'expand-window-left']    ,
-      \ 'J' : ['resize +5'  , 'expand-window-below']   ,
+      \ 'J' : [':resize +5'  , 'expand-window-below']   ,
       \ 'L' : ['<C-W>5>'    , 'expand-window-right']   ,
-      \ 'K' : ['resize -5'  , 'expand-window-up']      ,
+      \ 'K' : [':resize -5'  , 'expand-window-up']      ,
       \ '=' : ['<C-W>='     , 'balance-window']        ,
       \ 's' : ['<C-W>s'     , 'split-window-below']    ,
       \ 'v' : ['<C-W>v'     , 'split-window-below']    ,
@@ -219,7 +219,14 @@ let g:which_key_map.o = {
 " =======================================================
 " Create menus not based on existing mappings:
 " =======================================================
-" Provide commands(ex-command, <Plug>/<C-W>/<C-d> mapping, etc.) and descriptions for existing mappings
+" Provide commands(ex-command, <Plug>/<C-W>/<C-d> mapping, etc.)
+" and descriptions for the existing mappings.
+"
+" Note:
+" Some complicated ex-cmd may not work as expected since they'll be
+" feed into `feedkeys()`, in which case you have to define a decicated
+" Command or function wrapper to make it work with vim-which-key.
+" Ref issue #126, #133 etc.
 let g:which_key_map.b = {
       \ 'name' : '+buffer' ,
       \ '1' : ['b1'        , 'buffer 1']        ,