More fixes per some stuff Grinnz found

pod/perlfunc.pod

@@ -3900,7 +3900,6 @@ Returns a lowercased version of EXPR.  If EXPR is omitted, uses
 L<C<$_>|perlvar/$_>.
 
     my $str = lc("Perl is GREAT"); # "perl is great"
-    my $str = lc(undef);           # undef
 
 What gets returned depends on several factors:
 
@@ -3945,14 +3944,14 @@ Unicode rules are used for the case change.
 ASCII rules are used for the case change.  The lowercase of any character
 outside the ASCII range is the character itself.
 
+=back
+
 B<Note:> This is the internal function implementing the
 L<C<\L>|perlop/"Quote and Quote-like Operators"> escape in double-quoted
 strings.
 
     my $str = "Perl is \LGREAT\E"; # "Perl is great"
 
-=back
-
 =item lcfirst EXPR
 X<lcfirst> X<lowercase>
 
@@ -9346,7 +9345,6 @@ Returns an uppercased version of EXPR.  If EXPR is omitted, uses
 L<C<$_>|perlvar/$_>.
 
     my $str = uc("Perl is GREAT"); # "PERL IS GREAT"
-    my $str = uc(undef);           # undef
 
 This function behaves the same way under various pragmas, such as in a locale,
 as L<C<lc>|/lc EXPR> does.