Normalize filter string in symbol chooser

This just lowercases the filter string and removes spaces.
Remove method signature which is part of our SDK

Presumably this did not exist in the 10.6 SDK.
Remove next/previous properties on result (tree) node

We can get to the next/previous node via the parent pointer, although it has worse time complexity, it’s not something we use in loops, so the extra bookkeeping is not worth it.
Remove double semi-colons at end of line
Preserve selection when updating chooser items
Add OakAttributedStringForEventString helper function

This will convert the event string to the proper glyphs and lookup function key glyphs in the font and set the proper glyph info attributes (if found).
Use OakAttributedStringForEventString in bundle item chooser
Pass std::string instead of filter_string_t to rank_record