Pretty printing validation errors

[Linda-Njau]

This PR refactors the validation error pretty printer to make validation failures easier to read. This is a presentation-only change, validation behavior remains the same.

Previously, validation errors were printed as record-like structures. Once errors became nested (for example, records inside lists), the output was hard to follow and made it difficult to see what actually went wrong.

The main change is breaking validation errors into clearer sections. Errors are separated from the given data, and nested errors are presented in a way that makes the structure easier to follow.

For example, an invalid list error now looks like:

Invalid list:
  Errors (3):
  1) At index 0:
    Invalid shape:
      Expected: string
      Given: `1`

  2) At index 1:
    Invalid record:
      Errors (1):
      1) Missing field `name`

  3) At index 2:
    Invalid shape:
      Expected: string
      Given: `3`

  Given list:
    [0] = `1`
    [1] = `{"title": 2}`
    [2] = `3`
    [3] = `"ok"`

There are also a few smaller changes, such as rewording messages, explicitly counting and numbering errors, and other formatting improvements.

TBD: validation errors currently only display the entity name; I’m still working on including the file path in the error message.

[xvw]

So cool ! Thanks a lot @Linda-Njau

TBD: validation errors currently only display the entity name; I’m still working on including the file path in the error message.

Would you prefer that we split the review into several PRs, to introduce the file into another PR? And merge it as soon as possible?

[Linda-Njau]

So cool ! Thanks a lot @Linda-Njau

Thanks!

Would you prefer that we split the review into several PRs, to introduce the file into another PR? And merge it as soon as possible?

yes, I think that works great

[gr-im]

Cool ! I approve!
I think that it deserve a change entry!

[Linda-Njau]

Cool ! I approve!

Thanks!

I think that it deserve a change entry!

Sure, I’ll do that