Update check comments

The JavadocType and JavadocMethod checks are meant to check that the
Javadoc comments follow the appropriate format. On the other hand, the
MissingJavadocMethodCheck checks whether the method has missing Javadoc.

Let's update the comments to describe these checks.

config/checkstyle/checkstyle.xml

@@ -376,12 +376,12 @@
     JAVADOC CHECKS
     -->
 
-    <!-- Checks that every class, enumeration and interface have a header comment. -->
+    <!-- Checks the Javadoc's format for every class, enumeration and interface. -->
     <module name="JavadocType">
       <property name="allowMissingParamTags" value="true"/>
     </module>
 
-    <!-- Checks that every public method (excluding getters, setters and constructors) has a header comment. -->
+    <!-- Checks the Javadoc's format for every public method (excluding getters, setters and constructors). -->
     <module name="JavadocMethod">
       <property name="allowedAnnotations" value="Override, Test, BeforeAll, BeforeEach, AfterAll, AfterEach, Subscribe"/>
       <property name="accessModifiers" value="public"/>
@@ -393,6 +393,7 @@
 
     <module name="InvalidJavadocPosition"/>
 
+    <!-- Checks that every public method (excluding getters, setters and constructors) has a header comment. -->
     <module name="MissingJavadocMethodCheck">
       <property name="minLineCount" value="1"/>
       <property name="allowMissingPropertyJavadoc" value="true"/>