[orca] Ensure a voice is generated for listitem marker content

[Joanmarie Diggs <joanied src gnome org>]

commit 148ac525a2b002bb62a1752c90a9080ae33ba41a
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Wed Jun 12 15:20:10 2019 -0400

    Ensure a voice is generated for listitem marker content

 src/orca/speech_generator.py | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/src/orca/speech_generator.py b/src/orca/speech_generator.py
index b1583192c..949124740 100644
--- a/src/orca/speech_generator.py
+++ b/src/orca/speech_generator.py
@@ -1268,6 +1268,13 @@ class SpeechGenerator(generator.Generator):
         result.extend(self.voice(SYSTEM))
         return result
 
+    def _generateListItemMarker(self, obj, **args):
+        result = super()._generateListItemMarker(obj, **args)
+        if result:
+            result.extend(self.voice(DEFAULT))
+
+        return result
+
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