[Code Style] (Minor): code style and docs agreements review

[ala-n]

Points to update:

• [ ] JSDoc: method descriptions: /** Create something */ create() : Smth; vs /** Creates something */ create() : Smth;
• [ ] Head comment style
• [x] Discuss "Private" Handlers note in ESL Toggleable, because actually they are not so private...
• [ ] Using override keywoard
• [ ] TBD