Add option plugin_languages_details (#87)

tests/testscases.js

@@ -105,11 +105,16 @@
         plugin_languages:true,
         plugin_languages_colors:"complementary",
       }],
+      ["Language plugin (with details)", {
+        plugin_languages:true,
+        plugin_languages_details:"percentage",
+      }],
       ["Language plugin (complete)", {
         plugin_languages:true,
         plugin_languages_ignored:"html, css, dockerfile",
         plugin_languages_skipped:"metrics",
         plugin_languages_colors:"rainbow",
+        plugin_languages_details:"bytes-size, percentage",
       }],
       ["Follow-up plugin (default)", {
         plugin_followup:true,