Fix command syntax errors in IoT Edge docs

- Fix TOML syntax: use 'image =' instead of 'image:' in downstream edge device config examples
- Fix typo: 'iotege' to 'iotedge' in manage device certificates guide
- Fix wrong port: HTTPS:433 to HTTPS:443 in downstream device troubleshooting
- Fix missing verb in downstream device prerequisites

Author: jlian

articles/iot-edge/how-to-connect-downstream-device.md

@@ -51,7 +51,7 @@ Acquire the following to prepare your downstream device:
 
   This file is used to generate the Edge CA certificate in [Configure an IoT Edge device to act as a transparent gateway](how-to-create-transparent-gateway.md), and is available on your downstream device.
 
-  Your downstream device uses this certificate to check the identity of the gateway device. This trusted certificate  the transport layer security (TLS) connections to the gateway device. For usage details, see [Provide the root CA certificate](#provide-the-root-ca-certificate).
+  Your downstream device uses this certificate to check the identity of the gateway device. This trusted certificate secures the transport layer security (TLS) connections to the gateway device. For usage details, see [Provide the root CA certificate](#provide-the-root-ca-certificate).
 
 * A modified connection string that points to the gateway device.
 
@@ -233,7 +233,7 @@ If your downstream device connection to its gateway device is unstable, consider
 
 * Is the gateway hostname in the connection string the same as the hostname value in the IoT Edge config file on the gateway device?
 * Can the gateway hostname resolve to an IP address? Fix intermittent connections by using DNS or adding a host file entry on the downstream device.
-* Are communication ports open in your firewall? Make sure the required protocol ports (MQTTS:8883, AMQPS:5671, HTTPS:433) are open between the downstream device and the transparent IoT Edge device.
+* Are communication ports open in your firewall? Make sure the required protocol ports (MQTTS:8883, AMQPS:5671, HTTPS:443) are open between the downstream device and the transparent IoT Edge device.
 
 ## Next steps
 

articles/iot-edge/how-to-connect-downstream-iot-edge-device.md

@@ -524,7 +524,7 @@ You should already have IoT Edge installed on your device. If not, follow the st
     type = "docker"
 
     [agent.config]
-    image: "mcr.microsoft.com/azureiotedge-agent:1.5"
+    image = "mcr.microsoft.com/azureiotedge-agent:1.5"
     ```
 
 01. The beginning of your downstream configuration file should look similar to the following example.
@@ -841,7 +841,7 @@ name = "edgeAgent"
 type = "docker"
 
 [agent.config]
-image: "{Parent FQDN or IP}:443/azureiotedge-agent:1.5"
+image = "{Parent FQDN or IP}:443/azureiotedge-agent:1.5"
 ```
 
 If you're using a local container registry, or providing the container images manually on the device, update the config file accordingly.

articles/iot-edge/how-to-manage-device-certificates.md

@@ -562,7 +562,7 @@ Instead of manually managing the certificate files, IoT Edge has the built-in ab
 1. Apply the configuration
 
    ```bash
-   sudo iotege config apply
+   sudo iotedge config apply
    ```
 
 The following table lists what each option in `auto_renew` does: