Note: recreated in#6404

PR Checklist

• Addresses an existing open issue:fixesMake a "shortcut" API around TypeScript for node types #6244
• That issue was marked asaccepting prs
• Steps inCONTRIBUTING.md were taken

Overview

Adds toParserServicesWithTypeInformation the two most commonly used TypeScript type checking APIs:getSymbolAtLocation andgetTypeAtLocation. Then converts all places in code that I could find that used either after immediately retrieving the TS node for an ES node.

Also applies a few standardizations that helped me find-and-replace:

• const services = util.getParserServices(context) - not a variable namedparserServices, or variables from{ ... }
• const checker = services.program.getTypeChecker() - not a variable namedtypeChecker ortypes, and not an intermediateprogram variable

Updates theCustom Rules docs page to reflect this.