cmake: custom.md Fix format

docs/tutorials/cmake/custom.md

@@ -145,11 +145,13 @@ Replace `FEATURE_OPTION` with the name of the feature you want to enable or disa
 > [!TIP]
 > Some build definitions are present in the Kamailio codebase but are not yet exposed as dedicated CMake options.  
 > To set these, you can use the `EXTRA_DEFS` CMake option, which accepts a semicolon-separated list of definitions to pass to the build system.  
->  
+>
 > **Example usage:**  
+>
 > ```bash
 > cmake -S . -B build -DEXTRA_DEFS="DEFINITION;ANOTHER_DEF=VALUE"
 > ```
+>
 > Replace `DEFINITION` and `ANOTHER_DEF=VALUE` with the actual definitions you want to set.
 
 ### Example Command