Compiler "target" option capitalization in docs inconsistent with code and json schema

https://github.com/Microsoft/TypeScript/wiki/Compiler-Options says `--target` can take the value `ES5` (uppercase). Visual Studio Code warns about using the uppercase one in your `tsconfig.json`, presumably because it's following the schema. The JSON schema for `tsconfig.json` also has it in lowercase, but the docs (https://github.com/Microsoft/TypeScript/wiki/tsconfig.json#details) refer you to the first page (which uses uppercase) for the values. --- My guess at fixing the problem: From the source it appears the value ought to be lowercase: https://github.com/Microsoft/TypeScript/blob/master/src/compiler/commandLineParser.ts#L221 I think the fix is to use lowercase in the docs (the first page).