Fix mispelled "yield".

Author: fluca1978

doc/Language/syntax.pod6

@@ -694,7 +694,7 @@ method calls):
     =end code
 
 In the second method call the rightmost C<substr> is applied to "3" and not
-to the result of the leftmost C<substr>, which on the other hand yelds precedence
+to the result of the leftmost C<substr>, which on the other hand yields precedence
 to the rightmost one.
 
 =head1 Operators