Add diagram for scoped slots doc

[NataliaTepluhina]

Description of Problem

Currently, both slots and named slots have diagrams to illustrate the explanation. However, the scope slots chapter (which is the "hardest" to understand) lacks the visual explanation

Proposed Solution

A diagram is added for scoped slots

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[bencodezen]

Thanks so much for taking the time to create the diagram. Looks good to me!

[skirtles-code]

I'm wondering about the small differences from the code that comes just before the picture. e.g. The use of #default rather than v-slot and the extra <template> tag. The text just before the example emphasises that the example is showing a single default slot with v-slot, but the code style in the picture is more akin to working with named scoped slots.

[NataliaTepluhina]

@skirtles-code thank you for catching this! I've simplified a diagram to match the code, would you mind taking a second look? 🙏🏻

[skirtles-code]

Looks good!