[rb] Extend RBS support for logger and log entry

[aguspe]

Description

This PR expands RBS support for the following classes:

• Selenium::Webdriver::LogEntry
• Selenium::Webdriver::Logger

It also adds support for the standard library 'Forwardable' on the Steepfile

After the update on the RBS files for the LogEntry class this is the result:

The logger class keeps producing an error due to the proc signature coming from logger.formatted = not being identified, even though is part of the standard library:

Motivation and Context

This change expands the work done on: #12844

The main motivation behind it comes from: #10943

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[titusfortner]

The Logger class does not actually use the LogEntry class, so these are actually unrelated. That said, if this fixes an error, we might as well get it merged, thanks!

[aguspe]

The Logger class does not actually use the LogEntry class, so these are actually unrelated. That said, if this fixes an error, we might as well get it merged, thanks!

So the way I'm expanding RBS support is just by looking at the result of the Steep check and fixed the issues,
I did these two classes together just because they appeared in alphabetical order

My idea is to continue updating the type support in small PRs, containing two or three classes, so eventually when 'steep check' is run, there are no type issues