vim: add <Leader>] and <Leader>[ to move between definitions

`<Leader>[` moves to the start of the previous method/function/class
definition, `<Leader>]` to the start of the next

vim/shortcuts.vim

@@ -32,6 +32,11 @@ nmap <C-W>n :tabnext<CR>
 nmap <C-W>p :tabprev<CR>
 nmap <C-W>N :tabnew<CR>
 
+" move betweween methods, centering the method on each movement
+" [m moves to the start of the previous method, ]m to the end
+map <Leader>] ]mzz
+map <Leader>[ [mzz
+
 " open quickfix
 nmap <leader>cc :botright cope<CR>
 " open loclist