Fix miscellaneous Sphinx warnings (#244)

* /index.rst:24: WARNING: Line block ends without a blank line.

* /install.rst:300: WARNING: Explicit markup ends without a blank line; unexpected unindent.

* /admin.rst:273: WARNING: Could not lex literal_block as "http". Highlighting skipped.

* /tutorials/tut1.rst:150: WARNING: Could not lex literal_block as "json". Highlighting skipped.

* Remove extra newline

* Use integer value as epoch in JSON snippet

Even though using a string value is convenient (due to the lack of JSON
comments), it is confusing since the value should actually be an
integer. A slightly more verbose documentation is therefore preferable.

admin.rst

@@ -272,7 +272,7 @@ As discussed in :ref:`singular_plural`, there are no special URL forms for singu
 
 .. code:: http
 
-  GET /people?id=eq.1
+  GET /people?id=eq.1 HTTP/1.1
   Accept: application/vnd.pgrst.object+json
 
 This allows compound primary keys and makes the intent for singular response independent of a URL convention.

index.rst

@@ -21,6 +21,7 @@
   :target: https://www.paypal.me/postgrest
 
 |
+
 PostgREST is a standalone web server that turns your PostgreSQL database directly into a RESTful API. The structural constraints and permissions in the database determine the API endpoints and operations.
 
 Sponsors

install.rst

@@ -297,10 +297,11 @@ The database connection string above is just an example. Adjust the role and pas
   .. code-block:: bash
 
     listen_addresses = 'localhost,10.0.0.10'
+
   You might also need to add a new IPv4 local connection within pg_hba.conf. For instance:
-  
+
   .. code-block:: bash
-  
+
     host    all             all             10.0.0.10/32            trust
 
 Containerized PostgREST *and* db with docker-compose

tutorials/tut1.rst

@@ -151,9 +151,11 @@ Go back to jwt.io and change the payload to
 
   {
     "role": "todo_user",
-    "exp": <computed epoch value>
+    "exp": 123456789
   }
 
+**NOTE**: Don't forget to change the dummy epoch value :code:`123456789` in the snippet above to the epoch value returned by the psql command.
+
 Copy the updated token as before, and save it as a new environment variable.
 
 .. code-block:: bash