Add marker at first place of string mismatch

[Jujhar]

Addresses #6881

Summary

This is not final rather just a step I think, want to get your feedback and move accordingly.

Regarding the diffLocation() there might be a little extra performance usage here with the ^ location output I couldn't find the other code that generates it below.

Regarding the spaces discussion in #6881 I think if the spaces are shown with marker it should be obvious to 9/10 people that there is a difference there can add another section that shows if first character that is different is a xA0, em-dash, x20, dash, or similar then output symbol hex as well (Expected: 1x20234)

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[SimenB]

super cool idea, thanks for the PR! we've talked about substring diff highlighting before (#4619), but this might be a start that somewhat allows the feature? I'll defer to @pedrottimark here 🙂

[scotthovestadt]

Love the idea. Thanks for the PR.

The failing tests show a bug or two:

      "<dim>expect(</><red>received</><dim>).</>toBe<dim>(</><green>expected</><dim>) // Object.is equality</>
      
      Expected: <green>"without trailing space"</>
      Received: <red>"with<inverse> </></>
    - <red>trailing space"</>"
    + <red>trailing space"</>
    +                ^"

      at Object.toThrowErrorMatchingSnapshot (packages/expect/src/__tests__/matchers.test.js:225:43)

[pedrottimark]

@Jujhar Thank you for exploring a creative solution to this frustrating problem. It motivated us to implement a goal waiting more than a year to highlight substring differences in #8448

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