Add missing sub-heading for other examples

Signed-off-by: Michał Górny <[email protected]>

Author: mgorny

docs/how-to/advanced/cross-compilation.md

@@ -242,6 +242,8 @@ if [[ "$CONDA_BUILD_CROSS_COMPILATION" == "1" && "${mpi}" == "openmpi" ]]; then
 fi
 ```
 
+### Other examples
+
 There are more variations of this approach in the wild. So this is not meant to be exhaustive,
 but merely to provide a starting point with some guidelines. Please look at [other recipes for more examples](https://github.com/search?q=org%3Aconda-forge+path%3Arecipe%2Fmeta.yaml+%22%5Bbuild_platform+%21%3D+target_platform%5D%22&type=code).