Indenting property lists with keywords as property names

[Raffaele Ricciardi]

Hello there,

this is how Emacs Lisp Mode indents a property list with keywords as 
property names:

'(:a x
     :b y
     :c z)

I'm looking for a way to have the keywords aligned like this:

'(:a x
  :b y
  :c z)

Without resorting to rewriting the list like this:

(list :a 'x
      :b 'y
      :c 'z)

I've looked into the Lisp Indent Customize Group and into the Emacs 
Manuals to no avail.

Or is the code conceptually wrong from the beginning, as you are not 
expected to quote keywords? However, both (keyword :a) and (keyword ':a) 
return t.

Thanks.