Use SymbolFlags.TypeAlias when binding a jsdoc enum instead of SymbolFlags.Enum

[weswigham]

While working on #32372 I realized something - While the jsdoc tag is called @enum, behaviorally it does nothing like what a TS enum would do and does everything that a type alias would do (it is really like an @typedef with some extra checks). We should be able to remove heaps of special case code just by changing the flag we bind with and the associated declaration types.