fix: remove obsolete javadoc legacy flags for plugin 3.12.0

maven-javadoc-plugin 3.12.0 handles JPMS modules natively, so
legacyMode and sourceFileExcludes=module-info.java are no longer
needed. Added compile phase before javadoc generation to ensure
ANTLR sources are available for proper module resolution.

Author: mnesimiyilmaz

.github/workflows/javadoc.yml

@@ -27,10 +27,7 @@ jobs:
           cache: maven
 
       - name: Generate Javadoc
-        run: >-
-          ./mvnw javadoc:javadoc -q
-          -Dmaven.javadoc.legacyMode=true
-          -DsourceFileExcludes=module-info.java
+        run: ./mvnw compile javadoc:javadoc -q
 
       - name: Upload Pages artifact
         uses: actions/upload-pages-artifact@v4