Web3.py: remove block_number_formatter in favor of to_hex_if_integer

[kclowes]

• Version: 5.13 (to be released)

What was wrong?

In web3/_utils/method_formatters.py there is a method called block_number_formatter that is used for all of the block numbers. However, I also want to use it for a transaction index. I added a method called to_hex_if_integer that is the exact same functionality with a different name.

How can it be fixed?

This should be a straightforward replacement of block_number_formatter for to_hex_if_integer.

[tmckenzie51]

I can start working on this