Preserve ellipses when formatting parameter comments.

PiperOrigin-RevId: 488956140

Author: java-team-github-bot

core/src/main/java/com/google/googlejavaformat/CommentsHelper.java

@@ -46,5 +46,5 @@ static Optional<String> reformatParameterComment(Tok tok) {
 
   Pattern PARAMETER_COMMENT =
       Pattern.compile(
-          "/\\*\\s*(\\p{javaJavaIdentifierStart}\\p{javaJavaIdentifierPart}*)(\\Q...\\E)?\\s*=\\s*\\*/");
+          "/\\*\\s*(\\p{javaJavaIdentifierStart}\\p{javaJavaIdentifierPart}*(\\Q...\\E)?)\\s*=\\s*\\*/");
 }

core/src/test/resources/com/google/googlejavaformat/java/testdata/ParameterComment.input

@@ -23,4 +23,7 @@ class Q {
         /*k=*/ 1);
     g(/*a=*/ 1, /*b=*/ 1, /*c=*/ 1, /*d=*/ 1, /*e=*/ 1, /*f=*/ 1, /*g=*/ 1, /*h=*/ 1, /*i=*/ 1);
   }
+  static void h(Object... xs) {
+    h(/*xs...=*/ null);
+  }
 }

core/src/test/resources/com/google/googlejavaformat/java/testdata/ParameterComment.output

@@ -31,4 +31,8 @@ class Q {
         /* h= */ 1,
         /* i= */ 1);
   }
+
+  static void h(Object... xs) {
+    h(/* xs...= */ null);
+  }
 }