src/nft-helper: minor formatting fixes

Signed-off-by: Joachim Wiberg <[email protected]>

Author: troglobit

src/nft-helper/README.md

@@ -8,15 +8,15 @@ We could use a simple script for this, as shown below, and that would
 be fine if we had a POSIX shell in the container.  This helper is for
 the case when there is nothing.
 
-```
+```sh
 #!/bin/sh
 # nft wrapper to load rules at startup and flush at shutdown
 
 flush()
 {
-        echo "Got signal, stopping ..."
-	nft flush ruleset
-        exit 0
+    echo "Got signal, stopping ..."
+    nft flush ruleset
+    exit 0
 }
 
 trap flush INT TERM QUIT EXIT