Remove heading form installation `inc.md` file (#20697)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

docs/getting_started/installation/cpu/apple.inc.md

@@ -35,23 +35,22 @@ pip install -e .
 !!! note
     On macOS the `VLLM_TARGET_DEVICE` is automatically set to `cpu`, which currently is the only supported device.
 
-#### Troubleshooting
+!!! example "Troubleshooting"
+    If the build has error like the following snippet where standard C++ headers cannot be found, try to remove and reinstall your
+    [Command Line Tools for Xcode](https://developer.apple.com/download/all/).
 
-If the build has error like the following snippet where standard C++ headers cannot be found, try to remove and reinstall your
-[Command Line Tools for Xcode](https://developer.apple.com/download/all/).
-
-```text
-[...] fatal error: 'map' file not found
+    ```text
+    [...] fatal error: 'map' file not found
             1 | #include <map>
                 |          ^~~~~
         1 error generated.
         [2/8] Building CXX object CMakeFiles/_C.dir/csrc/cpu/pos_encoding.cpp.o
 
-[...] fatal error: 'cstddef' file not found
+    [...] fatal error: 'cstddef' file not found
             10 | #include <cstddef>
                 |          ^~~~~~~~~
         1 error generated.
-```
+    ```
 
 # --8<-- [end:build-wheel-from-source]
 # --8<-- [start:pre-built-images]