[CALCITE-6187] Linter should disallow tags such as '[MINOR]' in commi…

…t messages

core/src/test/java/org/apache/calcite/test/LintTest.java

@@ -346,6 +346,8 @@ private static boolean isJava(String filename) {
         hasSize(1));
     assertThat(f.apply("[CALCITE-4817] cannot start with lower-case", ""),
         hasItem("Message must start with upper-case letter"));
+    assertThat(f.apply("[MINOR] Lint", ""),
+        hasItem("starts with '[', and is not '[CALCITE-nnnn]'"));
 
     // If 'Lint:skip' occurs in the body, no checks are performed
     assertThat(
@@ -375,6 +377,9 @@ private static void checkMessage(String subject, String body,
             + "problem, not what you did");
       }
     }
+    if (subject2.startsWith("[")) {
+      consumer.accept("starts with '[', and is not '[CALCITE-nnnn]'");
+    }
     if (subject2.startsWith(" ")) {
       consumer.accept("starts with space");
     }