cli: add -nul-output compat

pkg/interp/args.jq

@@ -70,8 +70,12 @@ def args_parse($args; $opts):
     ( $opts
     | to_entries
     | map(
-        ( ({(.value.short): .key}? // {})
-        + ({(.value.long): .key}? // {})
+        ( . as $opt
+        | [.value.short // empty] +
+          [.value.long // empty] +
+          (.value.aliases // [])
+        | map({key: ., value: $opt.key})
+        | from_entries
         )
       )
     | add

pkg/interp/interp.jq

@@ -503,6 +503,8 @@ def _main:
       "null_output": {
         short: "-0",
         long: "--null-output",
+        # for jq compatibility
+        aliases: ["--nul-output"],
         description: "Null byte between outputs",
         bool: true
       },