docs: Improve snap build instructions
Make it clearer how to build the snap package manually.
@@ -22,10 +22,10 @@ $ sudo snap install kata-containers --classic
## Build and install snap image
-Run next command at the root directory of the packaging repository.
+Run the command below which will use the packaging Makefile to build the snap image:
```sh
-$ make snap
+$ make -C tools/packaging snap
```
To install the resulting snap image, snap must be put in [classic mode][3] and the
