Enforce alphabetical order for supported file types list (#531)

Signed-off-by: Richie Bendall <richiebendall@gmail.com>

.github/pull_request_template.md

@@ -11,7 +11,7 @@ If you're adding support for a new file type, please follow the below steps:
 	- Existing signatures requiring same sample length (same *signature group*) will be tested prior to your new detections. Yours will be last. (rational: common formats first).
 - Add the file extension to the `FileType` type in `core.d.ts`.
 - Add the file's MIME type to the `MimeType` type in `core.d.ts`.
-- Add the file extension to the `Supported file types` section in the readme, in the format ```- [`<extension>`](URL) - Format name```, for example, ```- [`png`](https://en.wikipedia.org/wiki/Portable_Network_Graphics) - Portable Network Graphics```
+- Add the file extension to the `Supported file types` section of the readme in alphabetical order, in the format ```- [`<extension>`](URL) - Format name```, for example, ```- [`png`](https://en.wikipedia.org/wiki/Portable_Network_Graphics) - Portable Network Graphics```
 - Add the file extension to the `keywords` array in the `package.json` file.
 - Run `$ npm test` to ensure the tests pass.
 - Open a pull request with a title like `Add support for Format`, for example, `Add support for PNG`.

package.json

@@ -204,6 +204,7 @@
 		"@tokenizer/token": "^0.3.0",
 		"@types/node": "^16.11.10",
 		"ava": "^3.15.0",
+		"commonmark": "^0.30.0",
 		"noop-stream": "^1.0.0",
 		"tsd": "^0.19.0",
 		"typescript": "^4.5.2",