Added documentation and example of W0133 Pointless Exception Statement Checker

[Bruce-8]

Motivation and Context

Checker W0133 (pointless-exception-statement) is one of the new checkers that recently got added to PythonTA. The changes made in this pull request provide a description for checker W0133 to ensure informed and proper usage.

Your Changes

Description: Added documentation of checker W0133 (pointless-exception-statement), created an example to display how error W0133 is triggered, and provided a correction to the example code that demonstrates how to resolve error W0133.

Type of change (select all that apply):

• Documentation update (change that modifies or updates documentation only)

Testing

Used a pylint scanner to ensure the example code emits and the correction resolves error W0133. Proofread the documentation of checker W0133 to ensure that the explanation is beginner-friendly and correct.

Questions and Comments (if applicable)

Checklist

• I have performed a self-review of my own code.
• I have verified that the CI tests have passed.
• I have reviewed the test coverage changes reported on Coveralls.

[david-yz-liu]

Just say "The exception below", the word 'statement' is a bit misleading since it's really the expression that isn't being used

[david-yz-liu]

Let's make this example a bit more realistic. Can you try something like the following (but please run pylint/PythonTA to make sure it actually triggers the error!):

def reciprocal(x: float) -> float:
    """Return 1 / x."""
    if x == 0:
        ValueError('x cannot be zero')  # Error on this line
    else:
        return 1 / x

and then in the documentation, show how to fix the error.

[david-yz-liu]

Based on the changes I've described below, you can remove this sentence.