refactor: use not so generic names

[tgpetrov]

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• All existing tests are passing
• Tests for the changes are included

What is the current behavior?

• There is a possible conflict when using generic method names like updateHandler. Follow-up of this PR
• Information about the expected format of date and time strings is not clear.

What is the new behavior?

• Name of a method is changed to decrease the chance of conflicts.
• The explanation about supported date/time formats is extended.

Fixes/Implements/Closes #[Issue Number].