Type fixes (#522)

* Typos

* Rewrite index.d.ts based on attw recommendations

See https://github.com/arethetypeswrong/arethetypeswrong.github.io/blob/main/docs/problems/MissingExportEquals.md

This required deleting some type tests.  Since the type tests are testing things that aren't exported, this may be acceptable.

* Add Are the Types Wrong to validate going forward

* Named export of PinoPretty

It's offered by the TypeScript types, but the JS didn't export it, which resulted in errors at runtime.

Readme.md

@@ -62,7 +62,7 @@ node app.js | pino-pretty
   feed, to the formatted log line.
 - `--errorProps` (`-e`): When formatting an error object, display this list
   of properties. The list should be a comma-separated list of properties Default: `''`.
-  Do not use this option if logging from pino@7. Support will be removed from future verions.
+  Do not use this option if logging from pino@7. Support will be removed from future versions.
 - `--levelFirst` (`-l`): Display the log level name before the logged date and time.
 - `--errorLikeObjectKeys` (`-k`): Define the log keys that are associated with
   error like objects. Default: `err,error`.