fix: update based on suggestion

Co-authored-by: Brian Smith <112954497+brian-smith-tcril@users.noreply.github.com>

oeps/architectural-decisions/oep-0058-arch-translations-management.rst

@@ -118,7 +118,7 @@ Proposed Implementation
 Move Translation Files to a New Repo
 ====================================
 
-Translation files (of types .mo and .po) currently exist amongst the code/documentation
+Translation files (of types .mo, .po, and .json) currently exist amongst the code/documentation
 they translate. We will move these translation files from being amongst the
 code/documentation to their own repo. For example, a translation file for the openedx
 repository `edx-platform`_ located at