Structural improvements

[tigerros]

This PR splits variations which are treated as one into two. It mostly affects "Accepted" and "Declined" variations, for example:

- Queen's Gambit Declined: ...
+ Queen's Gambit: Declined, ...

Apart from that, it also:

• Renames Réti Opening: Réti Accepted to Réti Opening: Réti Gambit, Accepted.
• Renames Queen's Pawn, Mengarini Attack to Queen's Pawn: Mengarini Attack.

This might be a bit controversial, but I don't see how "Accepted" or "Declined" is any different from a variation that has a name. Here's what I mean:

Blumenfeld Countergambit Accepted
Blumenfeld Countergambit: Spielmann Variation

What warrants "Accepted" to be a part of the "top-level" opening name, but not "Spielmann Variation"? It's a branch in the opening like any other, and should be formatted as such.

[TBestLittleHelper]

Argubly, more of an issue in Lila. But I wanted to point out that https://lichess.org/opening is not perfectly resistant to renames ( ie. b088bdd resulted in the text for stafford missing ).

Not sure if smaller changes like this will impact anything, but given the size it's worth keeping in mind. Most pages stll get their text from the wikibooks. I continue to dream of the day someone redesigns eco codes and they become useful as ID , so renames are safe. Anyway, the changes do LGTM

[tigerros]

Argubly, more of an issue in Lila. But I wanted to point out that https://lichess.org/opening is not perfectly resistant to renames ( ie. b088bdd resulted in the text for stafford missing ).

This makes it easier for programs to parse, assuming "Accepted" is meant to be treated like any other variation (which it, in my opinion, should).

Not sure if smaller changes like this will impact anything, but given the size it's worth keeping in mind. Most pages stll get their text from the wikibooks. I continue to dream of the day someone redesigns eco codes and they become useful as ID , so renames are safe. Anyway, the changes do LGTM

I would just assign a randomly generated code for each opening. Very easy to work with and carries no information (except the ID) so it's resistant to change. Books could just use an alphabetically sorted list of openings to make it friendlier towards users. Or if you really wanted categories, keep the ECO volumes but replace the numbers with the code, like A-9s4oh3. But of course, xkcd/927