Use shorter versions of end{whatever} in VimL

Instead of:

```vim
if {whatever}
endif

fun! {whatever}
endfun
```

This alters the vim-filetype settings to produce:

```vim
if {whatever}
end

fun! {whatever}
endf
```

These are not the absolute shortest commands (see below), just the ones
I prefer.

:en[dif]
:endfo[r]
:endf[unction]
:endt[ry]
:endw[hile]