Update ERC-4337: fix ERC-4337 format

[andysim3d]

When opening a pull request to submit a new EIP, please use the suggested template: https://github.com/ethereum/EIPs/blob/master/eip-template.md

We have a GitHub bot that automatically merges some PRs. It will merge yours immediately if certain criteria are met:

• The PR edits only existing draft PRs.
• The build passes.
• Your GitHub username or email address is listed in the 'author' header of all affected PRs, inside .
• If matching on email address, the email address is the one publicly listed on your GitHub profile.

[eip-review-bot]

File ERCS/erc-4337.md

Requires 1 more reviewers from @drortirosh, @forshtat, @kristofgazso, @shahafn, @tjade273, @vbuterin, @yoavw