fix incorrect json info and simplify the curl a bit

getting_started/sendmail.rst

@@ -10,19 +10,21 @@ endpoint is accessed with :code:`POST /api/outgoing-messages`. This API uses a P
 two examples, which use GET. Several pieces of information are required to send an email.
 
 * Mailsac API Key
-* To address
-* From address
-* Text
+* :code:`to` address
+* :code:`from` address
+* :code:`text` message text body
 
 Since emails without subjects frequently get marked as spam, we are also going to include a subject in our email. Our email
-message will be transmitted in JSON, therefore we have to set the content type to ::code:`Content-Type: application/json`.
-Our message data will be a comma separated key value array.
+message will be transmitted in JSON, therefore we must set the content type to ::code:`Content-Type: application/json`.
+Our message data will be a JSON object. Mailsac also supports sending raw
+SMTP text through this REST API - see the REST API specification for more info.
 
 .. code-block:: bash
     :caption: **Send an email**
 
-    curl --header "Content-Type: application/json" --request POST \
-    --data '{"_mailsacKey": "eoj1mn7x5y61w0egs25j6xrvs6lwrrld0oh43rj583cgdps10tokp2ceux9s6ri8eoj1mn7x5y6", \
-    "to": "recipient@gmail.com", "subject": "This is a test", "from": "sender@mailsac.com", \
-    "text": "This is a test"}' https://mailsac.com/api/outgoing-messages
+    curl -H "Content-Type: application/json" \
+        -H "Mailsac-Key: eoj1mn7x5y61w0egs25j6xrvs6lwrrl"
+        -X POST \
+        --data '{"to": "recipient@mailsac.com.com", "subject": "This is a test", "from": "my_sender@mailsac.com", "text": "This is a test"}' \
+        https://mailsac.com/api/outgoing-messages