Update regtest.sh comments

Co-authored-by: Zoe Faltibà <7492268+zoedberg@users.noreply.github.com>

Author: Arshia-r-m

regtest.sh

@@ -74,7 +74,7 @@ _start_services() {
             _die "port $port is already bound, services can't be started"
         fi
     done
-    # Start bitcoind first to avoid electrs failing if it races RPC availability.
+    # start bitcoind first to avoid depending services failing due to RPC unavailability
     $COMPOSE up -d bitcoind
     echo && echo "preparing bitcoind wallet"
     _wait_for_bitcoind