Change PokéSpe's Soudo and Shieldmilia to their English names

BUR #6935 has been approved by @nonamethanks.

rename tsurugi_soudo -> henry_sword
rename tate_shirudomiria -> casey_shield

The Sword and Shield arc had its first English volume released last month, and these are their English names.
https://bulbapedia.bulbagarden.net/wiki/Henry_Sword
https://bulbapedia.bulbagarden.net/wiki/Casey_Shield

I don't know whether I should request an alias or rename, because the tags are implied to their game counterparts and the help sections doesn't specify which action keeps existing implications. All I could find is that rename keeps Wiki history.

Only difference between an alias and a rename is that aliases creates a permanent redirection for searches and autocomplete from the old name. Everything else is identical.
Both aliases and renames move the implications to the new tag automatically.

The bulk update request #6935 (forum #195382) has been approved by @nonamethanks.