Update files.upload link in docs (#357)

* Update basic_usage.html

* Updated files.upload link

Author: Roach

docs-src/basic_usage.rst

@@ -331,7 +331,7 @@ Uploading files
           title="Test upload"
       )
 
-See `users.list <https://api.slack.com/methods/files.upload>`_ for more info.
+See `files.upload <https://api.slack.com/methods/files.upload>`_ for more info.
 
 
 --------

docs/basic_usage.html

@@ -413,7 +413,7 @@ <h2>Uploading files<a class="headerlink" href="#uploading-files" title="Permalin
     <span class="p">)</span>
 </pre></div>
 </div>
-<p>See <a class="reference external" href="https://api.slack.com/methods/files.upload">users.list</a> for more info.</p>
+<p>See <a class="reference external" href="https://api.slack.com/methods/files.upload">files.upload</a> for more info.</p>
 </div>
 <hr class="docutils" />
 <div class="section" id="web-api-rate-limits">
@@ -482,4 +482,4 @@ <h2>Web API Rate Limits<a class="headerlink" href="#web-api-rate-limits" title="
     <script async src='https://www.google-analytics.com/analytics.js'></script>
 
   </body>
-</html>
+</html>