docs: fix markdown lint issues in backend docs

docs/content/premiumizeme.md

@@ -12,16 +12,19 @@ Paths may be as deep as required, e.g. `remote:directory/subdirectory`.
 
 ## Configuration
 
-The initial setup for [premiumize.me](https://premiumize.me/) involves getting a token from premiumize.me which you
-need to do in your browser.  `rclone config` walks you through it.
+The initial setup for [premiumize.me](https://premiumize.me/) involves getting a
+token from premiumize.me which you need to do in your browser. `rclone config`
+walks you through it.
 
 Here is an example of how to make a remote called `remote`.  First run:
 
-     rclone config
+```sh
+rclone config
+```
 
 This will guide you through an interactive setup process:
 
-```
+```text
 No remotes found, make a new one?
 n) New remote
 s) Set configuration password
@@ -74,15 +77,21 @@ Once configured you can then use `rclone` like this,
 
 List directories in top level of your premiumize.me
 
-    rclone lsd remote:
+```sh
+rclone lsd remote:
+```
 
 List all the files in your premiumize.me
 
-    rclone ls remote:
+```sh
+rclone ls remote:
+```
 
 To copy a local directory to an premiumize.me directory called backup
 
-    rclone copy /home/source remote:backup
+```sh
+rclone copy /home/source remote:backup
+```
 
 ### Modification times and hashes