docs: improvements to 08-wasm docs

[crodriguezvega]

Description

• Some formatting fixes.
• Prepend homePath for data directory.

closes: #XXXX

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[aeryz]

Can we also fix here: https://github.com/cosmos/ibc-go/blob/carlos/08-wasm-docs-improvements/modules/light-clients/08-wasm/testing/simapp/app.go#L466

[damiannolan]

Thanks @crodriguezvega! LGTM!

I opened another one here with some follow up improvements/fixes #5920