Update docs

docs/src/content/docs/configuration/servers.mdx

@@ -4,7 +4,7 @@ Besides checking for local image updates, you might want to be able to view upda
 
 Just add something like this to your config:
 
-```json
+```jsonc
 {
     "servers": {
         "Cool server 1": "http://your-other-server-running-cup:8000",

docs/src/content/docs/configuration/socket.mdx

@@ -2,7 +2,7 @@
 
 If you need to specify a custom Docker socket (e.g. because you're using Podman), you can use the `socket` option. Here's an example:
 
-```json
+```jsonc
 {
   "socket": "/run/user/1000/podman/podman.sock"
   // Other options
@@ -11,7 +11,7 @@ If you need to specify a custom Docker socket (e.g. because you're using Podman)
 
 You can also specify a TCP socket if you're using a remote Docker host or a [proxy](https://github.com/Tecnativa/docker-socket-proxy):
 
-```json
+```jsonc
 {
   "socket": "tcp://localhost:2375"
   // Other options

docs/src/content/docs/configuration/theme.mdx

@@ -21,7 +21,7 @@ Available options are `default` and `blue`.
 
 Here's an example:
 
-```json
+```jsonc
 {
   "theme": "blue"
   // Other options