fix(ins): removed invalid content types

Author: bene2k1

compute/instances/how-to/use-boot-modes.mdx

@@ -72,17 +72,19 @@ Follow the instructions below to reboot an existing Instance using cloud-init.
 5. Enter your **user-data**. User data is the mechanism by which a user can pass information contained in a local file to an Instance at launch time. The typical use case is to pass something like a shell script or a configuration file as user data.
 
     Cloud-init supports different input formats for user-data:
-
+    <Message type="note">
+      Only the content type `text/plain` is supported.
+    </Message>
     |Format|Starts with|Description|
     | ---- | ------------- | --------- |
-    |**Cloud Config File**|`#cloud-config` or `Content-Type: text/cloud-config`| This file contains `cloud-config` data|
-    | **Shell Script**|`#!` or `Content-Type: text/x-shellscript`|A shell script will be executed at `rc.local` like level during first boot.|
-    |**Include File**|`#include` or `Content-Type: text/x-include-url`|An include file contains a list of one or different URLs, one per line. Each of the URLs will be read, and their content will be passed through this same set of rules. The content read from the URL can either be gzipped, mime-multi-part, or plain text.|
+    |**Cloud Config File**|`#cloud-config`| This file contains `cloud-config` data|
+    | **Shell Script**|`#!`|A shell script will be executed at `rc.local` like level during first boot.|
+    |**Include File**|`#include` |An include file contains a list of one or different URLs, one per line. Each of the URLs will be read, and their content will be passed through this same set of rules. The content read from the URL can either be gzipped, mime-multi-part, or plain text.|
     |**Gzip Compressed Content**||Gzip compressed content will be uncompressed and then be used as if it were not compressed. This is useful as user data is limited to 16384 bytes.|
     |**MIME multipart archive**||It is possible to specify more than one type of data by using a MIME multipart file. This can be used to specify both, a shell script and a cloud-config task.|
-    |**Upstart Job**| `#upstart-job` or `Content-Type: text/upstart-job`||
-    |**Cloud Boothook**|`#cloud-boothook` or `Content-Type: text/cloud-boothook`||
-    |**Part Handler**|Starts with `#part-handler` or `Content-Type: text/part-handler`||
+    |**Upstart Job**| `#upstart-job`||
+    |**Cloud Boothook**|`#cloud-boothook`||
+    |**Part Handler**|Starts with `#part-handler`||
 6. Click **Save**.
 7. Click **Reboot** in the top right corner of the page, and confirm the reboot of your Instance when prompted.