New check: mutated loop variable

[nickdrozd]

Current problem

Here's one I came across in the wild the other day:

for i in range(5):
    print(i)
    i += 1

Pylint doesn't have any problem with it. In the real-world case I saw, it didn't cause a change in behavior, but the variable mutation line was unintended and unneeded.

Desired solution

Mutating the variable of a for-loop is most likely a mistake, and in any case it's not a very good practice. I would like Pylint to flag it, and I think such a check could be enabled by default without too much difficulty.

Additional context

No response