Fix #6178: i18n: Captions missing in translations for hidden TOCs

tests/roots/test-intl/index.po

@@ -19,6 +19,9 @@ msgstr ""
 msgid "Table of Contents"
 msgstr "TABLE OF CONTENTS"
 
+msgid "Hidden Toc"
+msgstr "HIDDEN TOC"
+
 msgid "testdata for i18n"
 msgstr "TESTDATA FOR I18N"
 

tests/roots/test-intl/index.txt

@@ -30,3 +30,10 @@ CONTENTS
    refs
    section
    topic
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Hidden Toc
+   :hidden:
+
+   only