change(dev tools): Add an OUTPUT_DATA_LINE_LIMIT to zcash-rpc-diff

[teor2345]

Motivation

Some RPC outputs are very long, making them hard to paste into GitHub comments.

Solution

When RPC outputs are identical, only show the first 20 and last 20 lines

git diff already limits the length of its outputs. (I think?)

Review

This is a low priority developer tooling change.

Reviewer Checklist

• Are the PR labels correct?
• Does the code do what the ticket and PR says?
  • Does it change concurrent code, unsafe code, or consensus rules?
• How do you know it works? Does it have tests?

[oxarbitrage]

Can you show me where (in what RPC method) this modification was useful ?

An example output will be good enough.

[teor2345]

Can you show me where (in what RPC method) this modification was useful ?

An example output will be good enough.

There are some example outputs in this comment, click the triangles to show them:
#7450 (comment)

The original output was 2000 lines, now it's around 40 lines, so it's much easier to copy.

[oxarbitrage]

I like that the new action will only take effect when the outputs are identical.

Had a hard time trying to find an example, most of our rpc methods have at least some small difference with zcashd.

Examples in #7450 (comment) didn't worked for me (see #7450 (comment)).

However i made some dirty hacks here to check it out and everything looks good.