enforce proper range for rent burn_percent (#7217)

* enforce proper range for burn_percent

programs/stake/src/stake_state.rs

@@ -1394,7 +1394,7 @@ mod tests {
                 &Rent {
                     lamports_per_byte_year: 42,
                     ..Rent::default()
-                }
+                },
             ),
             Err(InstructionError::InsufficientFunds)
         );