Rename Edelgard from How Not to Summon a Demon Lord

The bulk update request #9286 has been approved by @evazion.

rename edelgard -> edelgard_(isekai_maou_to_shoukan_shoujo_no_dorei_majutsu)

As the title says.
The wiki also has "Not to be confused with Edelgard von Hresvelg.", which means that it should be qualified.

The bulk update request #9286 (forum #207721) has been approved by @evazion.

The series' shorthand isekaimaou (異世界魔王) would be a lot shorter than using the full title for the qualifier.

References:

• Official Website (Jpn): http://lanove.kodansha.co.jp/official/isekaimaou/
• Official Twitter (Jpn): https://twitter.com/isekaimaou
• Japanese Wikipedia

There are a few other character tags that needs updating then as well.

The bulk update request #9287 has been approved by @nonamethanks.

rename edelgard_(isekai_maou_to_shoukan_shoujo_no_dorei_majutsu) -> edelgard_(isekai_maou)
rename horn_(isekai_maou_to_shoukan_shoujo_no_dorei_majutsu) -> horn_(isekai_maou)
rename mei_(isekai_maou_to_shoukan_shoujo_no_dorei_majutsu) -> mei_(isekai_maou)
rename diablo_(isekai_maou_to_shoukan_shoujo_no_dorei_majutsu) -> diablo_(isekai_maou)
rename rose_(isekai_maou_to_shoukan_shoujo_no_dorei_majutsu) -> rose_(isekai_maou)
rename sylvie_(isekai_maou_to_shoukan_shoujo_no_dorei_majutsu) -> sylvie_(isekai_maou)

From full length to shorthand length title qualifier.

The bulk update request #9287 (forum #207735) has been approved by @nonamethanks.