docs: document new KVStore features, add some edge case tests (#1030) #4887

Job	Run time
check-changelog	0s
check-docusaurus	0s
Ensure that all required "cargo install" commands are run, or we have a cache hit (viceroy, 0.12.1)	2s
format	0s
Ensure that all required "cargo install" commands are run, or we have a cache hit (wasm-tools, 1....	2s
shellcheck	5s
Debug Build	3m 16s
Build (release)	8m 13s
Build (weval)	5m 37s
Run Web Platform Tests Debug	0s
sdktest-debug	0s
test-npm-package	0s
sdktest	0s
Run Web Platform Tests	0s
	17m 15s

Provide feedback