note multi hiding via non-multi in lexical scope (#1574)

Author: gfldex

doc/Language/functions.pod6

@@ -279,6 +279,10 @@ object:
 Unlike C<sub>, if you use named parameters with multi methods, the parameters must
 be required parameters to behave as expected.
 
+Please note that a non-multi sub or operator will hide multi candidates of the
+same name in any parent scope or child scope. The same is true for imported
+non-multi candidates.
+
 =head3 X<proto|declarator>
 
 C<proto> is a way to formally declare commonalities between C<multi>