getSignatureHelp broken for call with no leading whitespace

Signature help works for this: 
```
sub main()
  sayHello()
end sub
sub sayHello(name)
    print name
end sub
```
but not for this (note the missing whitespace before the call to sayHello):
```
sub main()
sayHello()
end sub
sub sayHello(name)
    print name
end sub
```