SSML tags are incorrectly ignored at end of sentence

[liaeh]

There is a bug where SSML tags are ignored if they occur at the end of a sentence, e.g. for marks and breaks.
E.g. for <s>No mark<mark name="before-time"/></s>, the tag marks_after is expected after the word mark, but is left out.

Another point is that neither the marks_before nor pause_before_ms are ever used, just the after variants.

Example:

from gruut import sentences

ssml_text = """<?xml version="1.0"?>
<speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://www.w3.org/2001/10/synthesis
                   http://www.w3.org/TR/speech-synthesis/synthesis.xsd"
         xml:lang="en-US">
  <s>No mark<mark name="before-time"/></s>
  <s>Yes<mark name="before-time"/> mark</s>
  <s>No break <break time="1s"/></s> 
  <s>With <break time="1s"/> break</s> 
</speak>"""

for sent in sentences(ssml_text, ssml=True):
    for word in sent:
        if word.phonemes:
            x = {
                "sent_idx": word.sent_idx,
                "lang": word.lang,
                "orig": word.text,
                "phones": list(word.phonemes),
                "is_punct": word.is_punctuation,
            }
            extras = [
                "marks_before",
                "marks_after",
                "pause_before_ms",
                "pause_after_ms",
            ]
            for extra in extras:
                attr_value = word.__getattribute__(extra)
                if attr_value:
                    x[extra] = attr_value
        print(x)

Outputs:

{'sent_idx': 0, 'lang': 'en-US', 'orig': 'No', 'phones': ['n', 'ˈoʊ'], 'is_punct': False}
{'sent_idx': 0, 'lang': 'en-US', 'orig': 'mark', 'phones': ['m', 'ˈɑ', 'ɹ', 'k'], 'is_punct': False}  # mark missing
{'sent_idx': 1, 'lang': 'en-US', 'orig': 'Yes', 'phones': ['j', 'ˈɛ', 's'], 'is_punct': False, 'marks_after': ['before-time']}  # mark there
{'sent_idx': 1, 'lang': 'en-US', 'orig': 'mark', 'phones': ['m', 'ˈɑ', 'ɹ', 'k'], 'is_punct': False}
{'sent_idx': 2, 'lang': 'en-US', 'orig': 'No', 'phones': ['n', 'ˈoʊ'], 'is_punct': False}
{'sent_idx': 2, 'lang': 'en-US', 'orig': 'break', 'phones': ['b', 'ɹ', 'ˈeɪ', 'k'], 'is_punct': False}  # pause missing
{'sent_idx': 3, 'lang': 'en-US', 'orig': 'With', 'phones': ['w', 'ˈɪ', 'θ'], 'is_punct': False, 'pause_after_ms': 1000}  # pause there
{'sent_idx': 3, 'lang': 'en-US', 'orig': 'break', 'phones': ['b', 'ɹ', 'ˈeɪ', 'k'], 'is_punct': False}