Update Math.round in es5.d.ts (#33920)
Update Math.round in es5.d.ts (#33920)

Update documentation of Math.round to reflect that it turns a float in to an integer and returns an integer.
Microsoft/TypeScript,microsoft/TypeScript,weswigham/TypeScript,nojvek/TypeScript,alexeagle/TypeScript,SaschaNaz/TypeScript,kitsonk/TypeScript,RyanCavanaugh/TypeScript,alexeagle/TypeScript,microsoft/TypeScript,minestarks/TypeScript,Microsoft/TypeScript,SaschaNaz/TypeScript,kpreisser/TypeScript,microsoft/TypeScript,kitsonk/TypeScript,alexeagle/TypeScript,SaschaNaz/TypeScript,kpreisser/TypeScript,RyanCavanaugh/TypeScript,Microsoft/TypeScript,SaschaNaz/TypeScript,minestarks/TypeScript,kpreisser/TypeScript,weswigham/TypeScript,minestarks/TypeScript,kitsonk/TypeScript,nojvek/TypeScript,nojvek/TypeScript,RyanCavanaugh/TypeScript,nojvek/TypeScript,weswigham/TypeScript