Improve WebClient documents to be more robust

Author: seratch

docs-src/web/index.rst

@@ -607,7 +607,7 @@ This library covers all the public endpoints as the methods in ``WebClient``. Th
     client = WebClient(token=os.environ['SLACK_BOT_TOKEN'])
     response = client.api_call(
         api_method='chat.postMessage',
-        json={'channel': '#random','text': "Hello world!"}
+        params={'channel': '#random','text': "Hello world!"}
     )
     assert response["message"]["text"] == "Hello world!"
 

docs/web/index.html

@@ -695,7 +695,7 @@ <h3>Calling any API methods<a class="headerlink" href="#calling-any-api-methods"
 <span class="n">client</span> <span class="o">=</span> <span class="n">WebClient</span><span class="p">(</span><span class="n">token</span><span class="o">=</span><span class="n">os</span><span class="o">.</span><span class="n">environ</span><span class="p">[</span><span class="s1">&#39;SLACK_BOT_TOKEN&#39;</span><span class="p">])</span>
 <span class="n">response</span> <span class="o">=</span> <span class="n">client</span><span class="o">.</span><span class="n">api_call</span><span class="p">(</span>
     <span class="n">api_method</span><span class="o">=</span><span class="s1">&#39;chat.postMessage&#39;</span><span class="p">,</span>
-    <span class="n">json</span><span class="o">=</span><span class="p">{</span><span class="s1">&#39;channel&#39;</span><span class="p">:</span> <span class="s1">&#39;#random&#39;</span><span class="p">,</span><span class="s1">&#39;text&#39;</span><span class="p">:</span> <span class="s2">&quot;Hello world!&quot;</span><span class="p">}</span>
+    <span class="n">params</span><span class="o">=</span><span class="p">{</span><span class="s1">&#39;channel&#39;</span><span class="p">:</span> <span class="s1">&#39;#random&#39;</span><span class="p">,</span><span class="s1">&#39;text&#39;</span><span class="p">:</span> <span class="s2">&quot;Hello world!&quot;</span><span class="p">}</span>
 <span class="p">)</span>
 <span class="k">assert</span> <span class="n">response</span><span class="p">[</span><span class="s2">&quot;message&quot;</span><span class="p">][</span><span class="s2">&quot;text&quot;</span><span class="p">]</span> <span class="o">==</span> <span class="s2">&quot;Hello world!&quot;</span>
 </pre></div>