chore: add a script to find files without new line at EOF

scripts/check-nl-at-eof.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+set -euo pipefail
+
+cd -P -- "$(dirname -- "$0")/.."
+
+nl_at_eof() {
+    local file="$1"
+    if ! [ -f $file ]; then
+        return
+    fi
+    case "$file" in
+        *.png|*rebar3)
+            return
+            ;;
+    esac
+    local lastbyte
+    lastbyte="$(tail -c 1 "$file" 2>&1)"
+    if [ "$lastbyte" != '' ]; then
+        echo $file
+    fi
+}
+
+while read -r file; do
+    nl_at_eof "$file"
+done < <(git ls-files)