convert some method arg handling from shift to unpacking

lib/PPI/Node.pm

@@ -714,40 +714,40 @@ sub __position {
 
 # Insert one or more elements before a child
 sub __insert_before_child {
-	my $self = shift;
-	my $key  = refaddr shift;
+	my ( $self, $child, @insertions ) = @_;
+	my $key  = refaddr $child;
 	my $p    = List::Util::first {
 	         refaddr $self->{children}[$_] == $key
 	         } 0..$#{$self->{children}};
-	foreach ( @_ ) {
+	foreach ( @insertions ) {
 		Scalar::Util::weaken(
 			$_PARENT{refaddr $_} = $self
 			);
 	}
-	splice( @{$self->{children}}, $p, 0, @_ );
+	splice( @{$self->{children}}, $p, 0, @insertions );
 	1;
 }
 
 # Insert one or more elements after a child
 sub __insert_after_child {
-	my $self = shift;
-	my $key  = refaddr shift;
+	my ( $self, $child, @insertions ) = @_;
+	my $key  = refaddr $child;
 	my $p    = List::Util::first {
 	         refaddr $self->{children}[$_] == $key
 	         } 0..$#{$self->{children}};
-	foreach ( @_ ) {
+	foreach ( @insertions ) {
 		Scalar::Util::weaken(
 			$_PARENT{refaddr $_} = $self
 			);
 	}
-	splice( @{$self->{children}}, $p + 1, 0, @_ );
+	splice( @{$self->{children}}, $p + 1, 0, @insertions );
 	1;
 }
 
 # Replace a child
 sub __replace_child {
-	my $self = shift;
-	my $old_child_addr  = refaddr shift;
+	my ( $self, $old_child, @replacements ) = @_;
+	my $old_child_addr  = refaddr $old_child;
 
 	# Cache parent of new children
 	my $old_child_index = List::Util::first {
@@ -756,14 +756,14 @@ sub __replace_child {
 
 	return undef if !defined $old_child_index;
 
-	foreach ( @_ ) {
+	foreach ( @replacements ) {
 		Scalar::Util::weaken(
 			$_PARENT{refaddr $_} = $self
 			);
 	}
 
 	# Replace old child with new children
-	splice( @{$self->{children}}, $old_child_index, 1, @_ );
+	splice( @{$self->{children}}, $old_child_index, 1, @replacements );
 
 	# Uncache parent of old child
 	delete $_PARENT{$old_child_addr};