Fix unmatched characters in Puppet lexer

[pyrmont]

The Puppet lexer does not match . or |, two valid characters. This PR fixes this bug.

[pyrmont]

The error was discovered during code review for #903.

@ananace, would you be able to have a look over this and see if you think it's still missing anything? I'm not familiar enough with Puppet to be the best judge.

[ananace]

It looks quite reasonable to me.

The only thing I can see that the current lexer wouldn't handle properly is complex string interpolations, things like;

notice("This computer has the following partitions:\n${facts["partitions"].map |$k,$v| { "$k mounted at ${v["mount"]} (${v["size"]})\n" }.join}")

(Though as this is a very niche use-case, it's probably not worth spending much time on if it's not a simple solution)

[pyrmont]

@ananace Yeah, that seems like something not worth worrying too much about at this stage. Thanks for looking at this so quickly—I'll merge this in and then rebase #903.

[jneen]

String interpolations shouldn't be difficult! It's what the stack model was made for :]

[pyrmont]

@jneen But I'm lazy :P