Parameter type validation for JSDuck should allow all primitive literals

[jdforrester]

Per the JSDuck documentation, values can be literals of booleans, numbers or strings. However, only the first of these works.

Literals which work

• {true}
• {false}
• {true|false}

  Literals which fail

• {'foo'}
• {"bar"}
• {'foo'|"bar"}
• {42}
• {42|24}

[Krinkle]

:+1:

[qfox]

Filed an issue at jsdoctypeparser Kuniwak/jsdoctypeparser#16