Task: Substitute LRNA with H2O

I believe you now call the omnipool representation "H2O" (water hydrates) instead of "LRNA", so you should update it everywhere you find it in the docs, especially [at this page](https://docs.hydration.net/omnipool_impermanent_loss/), which is linked from the UI in "Learn more about the risks" everytime a user deposits in the Omnipool (and will then possibily receive H2O, not LRNA):

Open the linked Omnipool impermanent-loss page and search the documentation for every occurrence of “LRNA”. Update the outdated terminology to “H2O”, especially on the page reached through the Omnipool risk link, then verify no documentation references still use the old name.

Written by the indexing model from the issue text.