schemas: fix ping requirements documentation

Changelog-None

Author: daywalker90

doc/schemas/ping.json

@@ -4,7 +4,7 @@
   "rpc": "ping",
   "title": "Command to check if a node is up.",
   "description": [
-    "The **ping** command checks if the node with *id* is ready to talk. It currently only works for peers we have a channel with."
+    "The **ping** command checks if the node with *id* is ready to talk. It only works for peers we are currently connected with."
   ],
   "request": {
     "required": [