Fix typo.

Author: Nick Hamann

src/libsyntax/parse/parser.rs

@@ -4564,7 +4564,7 @@ impl<'a> Parser<'a> {
         if try!(self.eat(&token::DotDot) ){
             if generics.is_parameterized() {
                 self.span_err(impl_span, "default trait implementations are not \
-                                          allowed to have genercis");
+                                          allowed to have generics");
             }
 
             try!(self.expect(&token::OpenDelim(token::Brace)));

src/test/compile-fail/syntaxt-default-trait-impls.rs

@@ -13,6 +13,6 @@
 trait MyDefaultImpl {}
 
 impl<T> MyDefaultImpl for .. {}
-//~^ ERROR default trait implementations are not allowed to have genercis
+//~^ ERROR default trait implementations are not allowed to have generics
 
 fn main() {}