message: fix(language-service): only use canonical symbols
  Language service was treating some alias TypeScript symbols as if
  they where the canonical symbol. If the symbol in scope is an alias
  of another symbol the symbol should be converted to the canonical
  symbol.
diff: @@ -811,10 +811,15 @@ class TypeWrapper implements Symbol {
  }
  class SymbolWrapper implements Symbol {
  + private symbol: ts.Symbol;
  private _tsType: ts.Type;
  private _members: SymbolTable;
  - constructor(private symbol: ts.Symbol, private context: TypeContext) {}
  + constructor(symbol: ts.Symbol, private context: TypeContext) {
  + this.symbol = symbol && context && (symbol.flags & ts.SymbolFlags.Alias) ?
  + context.checker.getAliasedSymbol(symbol) :
  + symbol;
  + }
  get name(): string { return this.symbol.name; }
  