XPath idents can't start with a star.

That is, names such as "*foo" are not valid. This was most likely a typo in the
first place.

lib/oga/xpath/lexer.rl

@@ -194,7 +194,7 @@ module Oga
         # Identifiers are used for element names, namespaces, attribute names,
         # etc. Identifiers have to start with a letter.
 
-        identifier = '*' | [a-zA-Z*_]+ [a-zA-Z\-_0-9]*;
+        identifier = '*' | [a-zA-Z_]+ [a-zA-Z\-_0-9]*;
 
         action emit_identifier {
           emit(:T_IDENT, ts, te)