Remove &eager sub form

This removes the &eager sub, which does not seem to exist.

(There's an .eager method and an eager statement prefix, but no sub)

Author: codesections

doc/Type/List.pod6

@@ -837,7 +837,6 @@ Examples:
 Defined as:
 
     multi method eager(List:D: --> List:D)
-    multi sub eager(*@elems --> List:D)
 
 Evaluates all elements in the C<List> eagerly, and returns them as a C<List>.