Update request handling documentation (#1741)

Contributes to #1531

docs/_static/css/default.css

@@ -1,4 +1,4 @@
 .rst-content .code-block-caption  {
     text-align: left;
-    padding: 0px, 0px, 5px, 5px;
+    padding: 0px 0px 5px 5px;
 }

docs/quickstart.rst

@@ -46,6 +46,7 @@ built using either the :code:`AsyncApp` or :code:`FlaskApp`.
         :sync: AsyncApp
 
         .. code-block:: python
+            :caption: **app.py**
 
             from connexion import AsyncApp
 
@@ -65,6 +66,7 @@ built using either the :code:`AsyncApp` or :code:`FlaskApp`.
             :code:`flask` extra.
 
         .. code-block:: python
+            :caption: **app.py**
 
             from connexion import FlaskApp
 
@@ -80,6 +82,7 @@ built using either the :code:`AsyncApp` or :code:`FlaskApp`.
         :sync: ConnexionMiddleware
 
         .. code-block:: python
+            :caption: **app.py**
 
             from asgi_framework import App
             from connexion import ConnexionMiddleware
@@ -91,6 +94,7 @@ built using either the :code:`AsyncApp` or :code:`FlaskApp`.
         You can also wrap a WSGI application leveraging the :code:`a2wsgi.WSGIMiddleware`:
 
         .. code-block:: python
+            :caption: **app.py**
 
             from wsgi_framework import App
             from connexion import ConnexionMiddleware