build: run docs regen in synth.py (#1059)

diff --git a/docs/dyn/texttospeech_v1beta1.voices.html b/docs/dyn/texttospeech_v1beta1.voices.html
index 438d6d1..df15156 100644
--- a/docs/dyn/texttospeech_v1beta1.voices.html
+++ b/docs/dyn/texttospeech_v1beta1.voices.html
@@ -103,12 +103,12 @@
     { # The message returned to the client by the `ListVoices` method.
     "voices": [ # The list of voices.
       { # Description of a voice supported by the TTS service.
-        "naturalSampleRateHertz": 42, # The natural sample rate (in hertz) for this voice.
         "languageCodes": [ # The languages that this voice supports, expressed as [BCP-47](https://www.rfc-editor.org/rfc/bcp/bcp47.txt) language tags (e.g. "en-US", "es-419", "cmn-tw").
           "A String",
         ],
-        "ssmlGender": "A String", # The gender of this voice.
         "name": "A String", # The name of this voice. Each distinct voice has a unique name.
+        "ssmlGender": "A String", # The gender of this voice.
+        "naturalSampleRateHertz": 42, # The natural sample rate (in hertz) for this voice.
       },
     ],
   }</pre>