[py] By and find_element Docstrings for IDE

[Andre-Medina]

Adding docstrings to the python code for By and Webdriver.find_element to show examples and key information when using IDE.

Description

Adding documentation to the following:

• py/selenium/webdriver/remote/webdriver.py to WebDriver.find_element
• py/selenium/webdriver/common/by.py to By

To generate better docstrings with examples

• in IDEs (e.g. VSC) and
• in the selenium api docs

Motivation and Context

Found there was no documentation which led to confusion for new developers. Came from discussing in related issue #14746

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.

[CLAassistant]

All committers have signed the CLA.

[shbenzer]

You can refer to this page for examples

[shbenzer]

Also once you've finished, run ./scripts/format.sh to help with linting