doc,lib,test: capitalize comment sentences

This activates the eslint capitalize comment rule for comments
above 50 characters.

PR-URL: https://github.com/nodejs/node/pull/24996
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-https-truncate.js

@@ -32,7 +32,7 @@ const https = require('https');
 const key = fixtures.readKey('agent1-key.pem');
 const cert = fixtures.readKey('agent1-cert.pem');
 
-// number of bytes discovered empirically to trigger the bug
+// Number of bytes discovered empirically to trigger the bug
 const data = Buffer.alloc(1024 * 32 + 1);
 
 httpsTest();