Declaring bash functions using the function keyword, with function body in parens

[DrHyde]

For bugs

• Rule Id (if any, e.g. SC1000):

SC1073, SC1065, SC1064, SC1072

• My shellcheck version (shellcheck --version or "online"):

0.9.0

• The rule's wiki page does not already cover this (e.g. https://shellcheck.net/wiki/SC2086)
• I tried on https://www.shellcheck.net/ and verified that this is still a problem on the latest commit

Here's a snippet or screenshot that shows the problem:

#!/usr/bin/env bash
function foo ( pwd )

Here's what shellcheck currently says:

$ shellcheck foo

In foo line 2:
function foo ( pwd )
^-- SC1073 (error): Couldn't parse this function. Fix to allow more checks.
               ^-- SC1065 (error): Trying to declare parameters? Don't. Use () and refer to params as $1, $2..


In foo line 3:

^-- SC1064 (error): Expected a { to open the function definition.
^-- SC1072 (error):  Fix any mentioned problems and try again.

For more information:
  https://www.shellcheck.net/wiki/SC1064 -- Expected a { to open the function...
  https://www.shellcheck.net/wiki/SC1065 -- Trying to declare parameters? Don...
  https://www.shellcheck.net/wiki/SC1072 --  Fix any mentioned problems and t...

Here's what I wanted or expected to see:

Either nothing, or if shellcheck strongly prefers that the function be defined as foo() ( pwd ) (it doesn't complain about that at all) it should say so.

Having the function body in parens instead of braces is kosher, it just means that the function body is executed in a sub-shell.