SpellBook Abridged for WoW Classic

        - Updated for Classic Era 1.15.9 and Anniversary 2.5.6
        - LEARNED_SPELL_IN_TAB was renamed to LEARNED_SPELL_IN_SKILL_LINE; the addon now registers whichever the client provides
        - Spellbook and spell lookups go through C_SpellBook / C_Spell when available, with fallback to the legacy globals
        - Fixed the LEARNED_SPELL_IN_SKILL_LINE branch of the event handler never running (typo "even")
        - Auto UpRank no longer fires while in combat and skips the useless scan for lower spellIDs
        - Removed the leftover dead code of the old rank filter, form highlighting and color config