add missed placeholder for log, delete redundant 'return' clause (apa…

…che#5550)

### Motivation

- Adjust code style

### Modifications

- Add the missing placeholder in log statement
- Delete redundant `return clause` for void method

pulsar-functions/instance/src/main/java/org/apache/pulsar/functions/instance/JavaInstanceRunnable.java

@@ -295,7 +295,6 @@ public void run() {
             if (stats != null) {
                 stats.incrSysExceptions(t);
             }
-            return;
         } finally {
             log.info("Closing instance");
             close();

pulsar-functions/worker/src/main/java/org/apache/pulsar/functions/worker/FunctionActioner.java

@@ -139,14 +139,12 @@ public void startFunction(FunctionRuntimeInfo functionRuntimeInfo) {
             functionRuntimeInfo.setRuntimeSpawner(runtimeSpawner);
 
             runtimeSpawner.start();
-            return;
         } catch (Exception ex) {
             FunctionDetails details = functionRuntimeInfo.getFunctionInstance()
                     .getFunctionMetaData().getFunctionDetails();
             log.info("{}/{}/{} Error starting function", details.getTenant(), details.getNamespace(),
                     details.getName(), ex);
             functionRuntimeInfo.setStartupException(ex);
-            return;
         }
     }
 

pulsar-functions/worker/src/main/java/org/apache/pulsar/functions/worker/FunctionRuntimeManager.java

@@ -230,7 +230,7 @@ public void initialize() {
                 }
             }
         } catch (Exception e) {
-            log.error("Failed to initialize function runtime manager: ", e.getMessage(), e);
+            log.error("Failed to initialize function runtime manager: {}", e.getMessage(), e);
             throw new RuntimeException(e);
         }
     }