rpc: unhide waitfor{block,newblock,blockheight}

They are now reliable. An earlier commit dropped their
IsRPCRunning() guards so they also work in the GUI.

doc/release-30635.md

@@ -1,4 +1,5 @@
 Updated RPCs
 ------------
 
-- The waitfornewblock RPC takes an optional `current_tip` argument. (#30635)
+- The waitfornewblock now takes an optional `current_tip` argument. It is also no longer hidden. (#30635)
+- The waitforblock and waitforblockheight RPCs are no longer hidden.  (#30635)

src/rpc/blockchain.cpp

@@ -3437,9 +3437,9 @@ void RegisterBlockchainRPCCommands(CRPCTable& t)
         {"blockchain", &getchainstates},
         {"hidden", &invalidateblock},
         {"hidden", &reconsiderblock},
-        {"hidden", &waitfornewblock},
-        {"hidden", &waitforblock},
-        {"hidden", &waitforblockheight},
+        {"blockchain", &waitfornewblock},
+        {"blockchain", &waitforblock},
+        {"blockchain", &waitforblockheight},
         {"hidden", &syncwithvalidationinterfacequeue},
     };
     for (const auto& c : commands) {