docs: update swagger for wasm

[brew0722]

Description

closes: #295

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[zemyblue]

@brew0722 , some example address's prefix of swagger is cosmos. So I think it is good to change to our prefix. Do you know how we could change this?

[brew0722]

@brew0722 , some example address's prefix of swagger is cosmos. So I think it is good to change to our prefix. Do you know how we could change this?

Probably independent of wasm, it seems to be an example recorded in swagger_legacy.yaml. swagger_legacy.yaml still has about gaia, tendermint, and cosmos throughout.

But as far as I know the REST API is deprecated(via lcd). So I will check to see if we need to continue supporting legacy REST APIs, and if necessary I will update them in a separate PR.

[zemyblue]

LGTM