english and punctuation fix

Author: gbhat618

src/main/java/org/jenkinsci/plugins/workflow/steps/SynchronousResumeNotSupportedException.java

@@ -43,9 +43,9 @@ public SynchronousResumeNotSupportedException() {
 
     public SynchronousResumeNotSupportedException(String stepDisplayFunctionName) {
         super(String.format("""
-            Step `%s` is a non-blocking synchronous step, it doesn't support resume after a restart. \
+            Step `%s` is a non-blocking synchronous step; it doesn't support resume after a restart. \
             You may wrap it within `retry(conditions: [nonresumable()], count: 2) {...}`, \
-            or in declarative syntax, use the `retries` option to an `agent` directive) to resume it.""",
+            or, in declarative syntax, use the `retries` option to an `agent` directive to resume it.""",
                             stepDisplayFunctionName)
         );
     }