docs(gno-js): Add provider instantiation docs #6229

Job	Run time
setup	3s
Run Main (gnodev) / Go Build / generated	7s
Run Main (gnodev) / Go Linter / lint	40s
Run Main (gnodev) / Go Test / test	1m 4s
Run Main (gnofaucet) / Go Build / generated	7s
Run Main (gnofaucet) / Go Linter / lint	20s
Run Main (gnofaucet) / Go Test / test	36s
Run Main (gnogenesis) / Go Build / generated	7s
Run Main (gnogenesis) / Go Linter / lint	37s
Run Main (gnogenesis) / Go Test / test	39s
Run Main (gnokeykc) / Go Build / generated	12s
Run Main (gnokeykc) / Go Linter / lint	22s
Run Main (gnokeykc) / Go Test / test	30s
Run Main (gnomd) / Go Build / generated	12s
Run Main (gnomd) / Go Linter / lint	17s
Run Main (gnomd) / Go Test / test	28s
Run Main (gnomigrate) / Go Build / generated	13s
Run Main (gnomigrate) / Go Linter / lint	22s
Run Main (gnomigrate) / Go Test / test	32s
	7m 28s

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