multi: replace FundingLocked and funding_locked strings

This commit is created by running the following commands,
```shell
find . -name "*.go" -exec sed -i '' 's/\"FundingLocked/\"ChannelReady/g' {} \;
find . -name "*.go" -exec sed -i '' 's/FundingLocked\"/ChannelReady\"/g' {} \;
find . -name "*.go" -exec sed -i '' 's/\ funding_locked/\ channel_ready/g' {} \;
```

lnwire/features.go

@@ -169,12 +169,12 @@ const (
 
 	// ScidAliasRequired is a required feature bit that signals that the
 	// node requires understanding of ShortChannelID aliases in the TLV
-	// segment of the funding_locked message.
+	// segment of the channel_ready message.
 	ScidAliasRequired FeatureBit = 46
 
 	// ScidAliasOptional is an optional feature bit that signals that the
 	// node understands ShortChannelID aliases in the TLV segment of the
-	// funding_locked message.
+	// channel_ready message.
 	ScidAliasOptional FeatureBit = 47
 
 	// PaymentMetadataRequired is a required bit that denotes that if an

lnwire/message.go

@@ -89,7 +89,7 @@ func (t MessageType) String() string {
 	case MsgFundingSigned:
 		return "MsgFundingSigned"
 	case MsgChannelReady:
-		return "FundingLocked"
+		return "ChannelReady"
 	case MsgShutdown:
 		return "Shutdown"
 	case MsgClosingSigned: