tools: capitalize sentences

This adds the `capitalized-comments` eslint rule to verify that
actual sentences use capital letters as starting letters. It ignores
special words and all lines below 62 characters.

PR-URL: https://github.com/nodejs/node/pull/24808
Reviewed-By: Sam Ruby <rubys@intertwingly.net>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

test/parallel/test-http2-server-push-stream-errors.js

@@ -64,7 +64,7 @@ const tests = specificTests.concat(genericTests);
 
 let currentError;
 
-// mock submitPushPromise because we only care about testing error handling
+// Mock submitPushPromise because we only care about testing error handling
 Http2Stream.prototype.pushPromise = () => currentError.ngError;
 
 const server = http2.createServer();