chore: More details to No UDF registered error (#15843)

Author: comphead

datafusion/core/src/execution/session_state.rs

@@ -1753,23 +1753,23 @@ impl FunctionRegistry for SessionState {
         let result = self.scalar_functions.get(name);
 
         result.cloned().ok_or_else(|| {
-            plan_datafusion_err!("There is no UDF named \"{name}\" in the registry")
+            plan_datafusion_err!("There is no UDF named \"{name}\" in the registry. Use session context `register_udf` function to register a custom UDF")
         })
     }
 
     fn udaf(&self, name: &str) -> datafusion_common::Result<Arc<AggregateUDF>> {
         let result = self.aggregate_functions.get(name);
 
         result.cloned().ok_or_else(|| {
-            plan_datafusion_err!("There is no UDAF named \"{name}\" in the registry")
+            plan_datafusion_err!("There is no UDAF named \"{name}\" in the registry. Use session context `register_udaf` function to register a custom UDAF")
         })
     }
 
     fn udwf(&self, name: &str) -> datafusion_common::Result<Arc<WindowUDF>> {
         let result = self.window_functions.get(name);
 
         result.cloned().ok_or_else(|| {
-            plan_datafusion_err!("There is no UDWF named \"{name}\" in the registry")
+            plan_datafusion_err!("There is no UDWF named \"{name}\" in the registry. Use session context `register_udwf` function to register a custom UDWF")
         })
     }