IMP: new tag in file to tell that the script should pass shellcheck

The `# run-shellchek` tag must be placed in the first 10 lines of the
file

shellcheck/docker_build_and_run_shellcheck.sh

@@ -1,4 +1,7 @@
 #!/bin/bash
+# run-shellcheck
+# usage : $0 [shell script to check]
+# called without arguments, il will shellcheck any *.sh file found in the project
 set -e
 
 dockerfile="$(dirname "$0")/Dockerfile.shellcheck"