javadoc: Add bunch of option arg (non)completions

Author: scop

completions/java

@@ -240,6 +240,11 @@ _javadoc()
             _filedir '?(x)htm?(l)'
             return
             ;;
+        -doclet|-exclude|-subpackages|-source|-locale|-encoding|-windowtitle|\
+        -doctitle|-header|-footer|-top|-bottom|-group|-noqualifier|-tag|\
+        -charset|-sourcetab|-docencoding)
+            return
+            ;;
         -stylesheetfile)
             _filedir css
             return
@@ -248,10 +253,15 @@ _javadoc()
             _filedir -d
             return
             ;;
-        -classpath|-bootclasspath|-docletpath|-sourcepath|-extdirs)
+        -classpath|-cp|-bootclasspath|-docletpath|-sourcepath|-extdirs|\
+        -excludedocfilessubdir)
             _java_path
             return
             ;;
+        -helpfile)
+            _filedir
+            return
+            ;;
     esac
 
     # -linkoffline takes two arguments