fix: Add missing commas

* Add missing commas to `ctexplain` text

Closes #14666.

PiperOrigin-RevId: 425702114

tools/ctexplain/bazel_api_test.py

diff --git a/tools/ctexplain/bazel_api_test.py b/tools/ctexplain/bazel_api_test.py
index e3d404c..a78160f 100644
--- a/tools/ctexplain/bazel_api_test.py
+++ b/tools/ctexplain/bazel_api_test.py
@@ -134,10 +134,12 @@
 
   def testConfigWithStarlarkFlags(self):
     self.ScratchFile('testapp/defs.bzl', [
-        'def _flag_impl(settings, attr):', '  pass', 'string_flag = rule(',
+        'def _flag_impl(settings, attr):',
+        '  pass',
+        'string_flag = rule(',
         '  implementation = _flag_impl,',
-        '  build_setting = config.string(flag = True)'
-        ')'
+        '  build_setting = config.string(flag = True)',
+        ')',
     ])
     self.ScratchFile('testapp/BUILD', [
         'load(":defs.bzl", "string_flag")',