Add 'stuff' module jsdoc to sphinx

This commit adds the autogenerated jsdoc output to our sphinx
documentation. Its main purpose is to serve as a proof of concept for
the new jsdoc-sphinx setup.
As part of this, the jsdoc markup within ``stuff.js`` had to be fixed as
the previous version was invalid.

Ref.: #257

docs/index.rst

@@ -24,3 +24,4 @@ or feel that topics are not covered properly.
    packaging
    versioning
    styleguide
+   jsdoc/index

docs/jsdoc/index.rst

@@ -0,0 +1,8 @@
+Index of Autodocumented (JSDoc) code
+=====================================
+
+
+.. toctree::
+
+    extension
+    Stuff

docs/jsdoc/stuff.rst

@@ -0,0 +1,6 @@
+Stuff.js
+========
+
+.. autofunction:: formatDuration
+.. autofunction:: formatDurationHuman
+.. autofunction:: formatDurationHours

extension/stuff.js

@@ -23,10 +23,10 @@ Copyright (c) 2016 - 2018 Eric Goller / projecthamster <elbenfreund@projecthamst
 
 // Time formatting helpers
 
-/* @function formatDuration
- *
+/**
  * Return time-information formatted as '%HH:%MM'
  *
+ * @function
  * @param {int} - Total amount of seconds to represent.
  */
 function formatDuration(total_seconds) {
@@ -38,11 +38,11 @@ function formatDuration(total_seconds) {
     // This string formatting is not part of JS canon but provided by the shell environment.
     return "%02d:%02d".format(hours, minutes);
 }
-
-/* @function formatDurationHuman
- *
+/**
  * Return time-information as '%HHh %SSmin' or '%SSmin' (if hours=0).
  *
+ * @function
+ *
  * @param {int} - Total amount of seconds to represent.
  */
 function formatDurationHuman(total_seconds) {
@@ -68,11 +68,11 @@ function formatDurationHuman(total_seconds) {
     return result;
 }
 
-/* @function formatDurationHours
- *
+/**
  * Return time-information as decimal (with one decimal place) amount of hours.
  * Example: 'X.Yh'
  *
+ * @function
  * @param {int} - Total amount of seconds to represent.
  */
 function formatDurationHours(seconds) {