Docs: typos, formatting

[ci skip]

docs/esps/mailgun.rst

@@ -1,7 +1,7 @@
 .. _mailgun-backend:
 
 Mailgun
--------
+=======
 
 Anymail integrates with the `Mailgun <https://mailgun.com>`_
 transactional email service from Rackspace, using their
@@ -9,7 +9,7 @@ REST API.
 
 
 Settings
-========
+--------
 
 .. rubric:: EMAIL_BACKEND
 
@@ -56,7 +56,7 @@ The default is ``MAILGUN_API_URL = "https://api.mailgun.net/v3"``
 .. _mailgun-sender-domain:
 
 Email sender domain
-===================
+-------------------
 
 Mailgun's API requires a sender domain `in the API url <base-url>`_.
 By default, Anymail will use the domain of each email's from address
@@ -86,8 +86,10 @@ to all messages:
 .. _base-url: https://documentation.mailgun.com/api-intro.html#base-url
 
 
-Mailgun esp_extra
-=================
+.. _mailgun-esp-extra:
+
+exp_extra support
+-----------------
 
 Anymail's Mailgun backend will pass all :attr:`~anymail.message.AnymailMessage.esp_extra`
 values directly to Mailgun. You can use any of the (non-file) parameters listed in the

docs/esps/mandrill.rst

@@ -1,14 +1,14 @@
 .. _mandrill-backend:
 
 Mandrill
---------
+========
 
 Anymail integrates with the `Mandrill <http://mandrill.com/>`_
 transactional email service from MailChimp.
 
 
 Settings
-========
+--------
 
 .. rubric:: EMAIL_BACKEND
 
@@ -50,8 +50,10 @@ which is the secure, production version of Mandrill's 1.0 API.
 (It's unlikely you would need to change this.)
 
 
-Mandrill esp_extra
-==================
+.. _mandrill-esp-extra:
+
+esp_extra support
+-----------------
 
 Anymail's Mandrill backend does not yet implement the
 :attr:`~anymail.message.AnymailMessage.esp_extra` feature.
@@ -60,7 +62,7 @@ Anymail's Mandrill backend does not yet implement the
 .. _migrating-from-djrill:
 
 Migrating from Djrill
-=====================
+---------------------
 
 Anymail has its origins as a fork of the `Djrill`_
 package, which supported only Mandrill. If you are migrating

docs/esps/sendgrid.rst

@@ -88,6 +88,8 @@ The default is ``SENDGRID_API_URL = "https://api.sendgrid.com/api/"``
 (It's unlikely you would need to change this.)
 
 
+.. _sendgrid-esp-extra:
+
 esp_extra support
 -----------------
 
@@ -132,7 +134,7 @@ Limitations and quirks
 
 **Message-ID**
   SendGrid does not return any sort of unique id from its send API call.
-  Knowing a sent message's ID can important for later queries about
+  Knowing a sent message's ID can be important for later queries about
   the message's status.
 
   To work around this, Anymail generates a new Message-ID for each