Just: print the error prefix instead of the word for it

The prefix was written `{error}`, which is Python's spelling. just interpolates
with `{{ }}`, so every internal-checkout failure said `{error}` where it meant a
red `error:`. It is the only single-brace interpolation in any justfile here.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: redsun82

misc/just/defs.just

@@ -65,7 +65,7 @@ default_db_checks := ['--check-databases', '--check-diff-informed', '--fail-on-t
 [no-exit-message]
 @_require_semmle_code:
     {{ if SEMMLE_CODE == "" { f'''
-        echo "{error} running this recipe requires doing so from an internal repository checkout" >&2
+        echo "{{ error }}running this recipe requires doing so from an internal repository checkout" >&2
         exit 1
     ''' } else { "" } }}