Add docs for --keyofStringsOnly, --declarationMap and --resolveJsonModule`

Addresses microsoft/TypeScript#23627

Author: mhegazy

pages/Compiler Options.md

@@ -12,6 +12,7 @@ Option                                         | Type      | Default
 `--checkJs`                                    | `boolean` | `false`                        | Report errors in `.js` files. Use in conjunction with `--allowJs`.
 `--declaration`<br/>`-d`                       | `boolean` | `false`                        | Generates corresponding `.d.ts` file.
 `--declarationDir`                             | `string`  |                                | Output directory for generated declaration files.
+`--declarationMap`                             | `boolean` | `false`                        | Generates a sourcemap for each corresponding '.d.ts' file.
 `--diagnostics`                                | `boolean` | `false`                        | Show diagnostic information.
 `--disableSizeLimit`                           | `boolean` | `false`                        | Disable size limitation on JavaScript project.
 `--downlevelIteration`                         | `boolean` | `false`                        | Provide full support for iterables in `for..of`, spread and destructuring when targeting ES5 or ES3.
@@ -29,6 +30,7 @@ Option                                         | Type      | Default
 `--isolatedModules`                            | `boolean` | `false`                        | Transpile each file as a separate module (similar to "ts.transpileModule").
 `--jsx`                                        | `string`  | `"Preserve"`                   | Support JSX in `.tsx` files: `"React"` or `"Preserve"`. See [JSX](./JSX.md).
 `--jsxFactory`                                 | `string`  | `"React.createElement"`        | Specify the JSX factory function to use when targeting react JSX emit, e.g. `React.createElement` or `h`.
+`--keyofStringsOnly`                           | `boolean`  | `false`                       | Resolve `keyof` to string valued property names only (no numbers or symbols).
 `--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`  <br/>► `ES2018` <br/>► `ESNext` <br/>► `DOM` <br/>► `DOM.Iterable` <br/>► `WebWorker` <br/>► `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.Intl` <br/>► `ES2017.SharedMemory` <br/>► `ES2017.TypedArrays` <br/>► `ES2018.Intl` <br/>► `ES2018.Promise` <br/>► `ES2018.RegExp` <br/>► `ESNext.AsyncIterable` <br/>► `ESNext.Array` <br/><br/> Note: If `--lib` is not specified a default list of librares are injected. The default libraries injected are:  <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.
@@ -63,6 +65,7 @@ Option                                         | Type      | Default
 `--project`<br/>`-p`                           | `string`  |                                | Compile a project given a valid configuration file.<br/>The argument can be a file path to a valid JSON configuration file, or a directory path to a directory containing a `tsconfig.json` file.<br/>See [tsconfig.json](./tsconfig.json.md) documentation for more details.
 `--reactNamespace`                             | `string`  | `"React"`                      | DEPRECATED. Use `--jsxFactory` instead.<br/>Specifies the object invoked for `createElement` and `__spread` when targeting `"react"` JSX emit.
 `--removeComments`                             | `boolean` | `false`                        | Remove all comments except copy-right header comments beginning with `/*!`
+`--resolveJsonModule`                          | `boolean` | `false`                        | Include modules imported with `.json` extension.
 `--rootDir`                                    | `string`  | *(common root directory is computed from the list of input files)*   | Specifies the root directory of input files. Only use to control the output directory structure with `--outDir`.
 `rootDirs`<sup>[2]</sup>                       | `string[]`|                                | List of <i>root</i> folders whose combined content represent the structure of the project at runtime. See [Module Resolution documentation](./Module Resolution.md#virtual-directories-with-rootdirs) for more details.
 `--skipDefaultLibCheck`                        | `boolean` | `false`                        | DEPRECATED. Use `--skipLibCheck` instead.<br/>Skip type checking of [default library declaration files](./Triple-Slash Directives.md#-reference-no-default-libtrue).