NumberFormatException when doing lookup with a decimal

[mschoeb]

Lookup with a decimal should not parse and result in a parser error. Currently, the xquery parser accepts any number and then fails when trying to turn it into an integer. Our parsers both do not differentiate between Integers and other numbers

The fix is to change
keySpecifier : ( in=Literal| lt=stringLiteral | nc=NCName | pe=parenthesizedExpr | vr=varRef | wc='*');
to something like
keySpecifier : ( in=IntegerLiteral| lt=stringLiteral | nc=NCName | pe=parenthesizedExpr | vr=varRef | wc='*');

But this is not straightforward as the lexer will still turn it into a Literal and the parser cant find it. Putting the IntegerLiteral lexer rule higher results in other things breaking (IntegerLiteral appearing where Literal is expected)