docs: updating v7 migration doc with generic state verification methods

docs/.vuepress/config.js

@@ -375,6 +375,11 @@ module.exports = {
               directory: false,
               path: "/migrations/v5-to-v6.html",
             },
+            {
+              title: "IBC-Go v6 to v7",
+              directory: false,
+              path: "/migrations/v6-to-v7.html",
+            },
           ],
         },
         {

docs/migrations/v6-to-v7.md

@@ -117,7 +117,37 @@ The `CheckMisbehaviourAndUpdateState` function has been removed from `ClientStat
 
 The function `GetTimestampAtHeight` has been added to the `ClientState` interface. It should return the timestamp for a consensus state associated with the provided height.
 
-A zero proof height is now allowed by core IBC and may be passed into `VerifyMembership` and `VerifyNonMembership`. Light clients are responsible for returning an error if a zero proof height is invalid behaviour. 
+Prior to ibc-go/v7 the `ClientState` interface defined a method for each data type which was being verified in the counterparty state store.
+The state verification functions for all IBC data types have been consolidated into two generic methods, `VerifyMembership` and `VerifyNonMembership`.
+Both are expected to be provided with a standardised key path, `exported.Path`, as defined in [ICS 24 host requirements](https://github.com/cosmos/ibc/tree/main/spec/core/ics-024-host-requirements). Membership verification requires callers to provide the marshalled value `[]byte`. Delay period values should be zero for non-packet processing verification. A zero proof height is now allowed by core IBC and may be passed into `VerifyMembership` and `VerifyNonMembership`. Light clients are responsible for returning an error if a zero proof height is invalid behaviour. 
+
+See below for an example of how ibc-go now performs channel state verification.
+
+```go
+merklePath := commitmenttypes.NewMerklePath(host.ChannelPath(portID, channelID))
+merklePath, err := commitmenttypes.ApplyPrefix(connection.GetCounterparty().GetPrefix(), merklePath)
+if err != nil {
+    return err
+}
+
+channelEnd, ok := channel.(channeltypes.Channel)
+if !ok {
+    return sdkerrors.Wrapf(sdkerrors.ErrInvalidType, "invalid channel type %T", channel)
+}
+
+bz, err := k.cdc.Marshal(&channelEnd)
+if err != nil {
+    return err
+}
+
+if err := clientState.VerifyMembership(
+    ctx, clientStore, k.cdc, height,
+    0, 0, // skip delay period checks for non-packet processing verification
+    proof, merklePath, bz,
+); err != nil {
+    return sdkerrors.Wrapf(err, "failed channel state verification for client (%s)", clientID)
+}
+```
 
 ### `Header` and `Misbehaviour`