Add more comments on default library with no --lib

Fixes microsoft/TypeScript#11093

Author: mhegazy

pages/Compiler Options.md

@@ -22,7 +22,7 @@ Option                                         | Type      | Default
 `--init`                                       |           |                                | Initializes a TypeScript project and creates a `tsconfig.json` file.
 `--isolatedModules`                            | `boolean` | `false`                        | Unconditionally emit imports for unresolved files.
 `--jsx`                                        | `string`  | `"Preserve"`                   | Support JSX in '.tsx' files: `'React'` or `'Preserve'`. See [JSX](./JSX.md).
-`--lib`                                        | `string[]`|                                | List of library files to be included in the compilation.</br>Possible values are:  <br/>► `es5` <br/>► `es6` <br/>► `es2015` <br/>► `es7` <br/>► `es2016` <br/>► `es2017` `dom` `webworker` `scripthost` <br/>► `es2015.core` <br/>► `es2015.collection` <br/>► `es2015.generator` <br/>► `es2015.iterable` <br/>► `es2015.promise` <br/>► `es2015.proxy` <br/>► `es2015.reflect` <br/>► `es2015.symbol` <br/>► `es2015.symbol.wellknown` <br/>► `es2016.array.include` <br/>► `es2017.object` <br/>► `es2017.sharedmemory`
+`--lib`                                        | `string[]`|                                | List of library files to be included in the compilation.</br>Possible values are:  <br/>► `es5` <br/>► `es6` <br/>► `es2015` <br/>► `es7` <br/>► `es2016` <br/>► `es2017` `dom` `webworker` `scripthost` <br/>► `es2015.core` <br/>► `es2015.collection` <br/>► `es2015.generator` <br/>► `es2015.iterable` <br/>► `es2015.promise` <br/>► `es2015.proxy` <br/>► `es2015.reflect` <br/>► `es2015.symbol` <br/>► `es2015.symbol.wellknown` <br/>► `es2016.array.include` <br/>► `es2017.object` <br/>► `es2017.sharedmemory` <br/><br/> Note: If `--lib` is not specified a default library is injected. The default library injected is:  <br/> ► For `--target ES5`: `dom,es5,scripthost`</br>  ► For `--target ES6`: `dom,es6,dom.iterable,scripthost`
 `--listEmittedFiles`                           | `boolean` | `false`                        | Print names of generated files part of the compilation.
 `--listFiles`                                  | `boolean` | `false`                        | Print names of files part of the compilation.
 `--locale`                                     | `string`  | *(platform specific)*          | The locale to use to show error messages, e.g. en-us.