SentenceTransformersTokenTextSplitter Doesn't Preserve Text
Labels: name: auto:bug

### System Info

```
from langchain.text_splitter import SentenceTransformersTokenTextSplitter
splitter = SentenceTransformersTokenTextSplitter(
    tokens_per_chunk=64,
    chunk_overlap=0,
    model_name='intfloat/e5-base-v2',
    add_start_index=True,
)
text = "- afrikaans\n- العربية\n- azərbaycanca\n- বাংলা\n- беларуская\n- bosanski\n- čeština\n- deutsch\n- eesti\n- ελληνικά\n- español\n- فارسی\n- français\n- gaeilge\n- 한국어\n- հայերեն\n- bahasa indonesia\n- עברית\n- jawa\n- kurdî\n- latviešu\n- lietuvių\n- македонски\n- malti\n- मराठी\n- مصرى\n- bahasa melayu\n- nederlands\n- 日本語\n- oʻzbekcha / ўзбекча\n- ਪੰਜਾਬੀ\n- پنجابی\n- پښتو\n- português\n- română\n- русский\n- simple english\n- کوردی\n- suomi\n- తెలుగు\n- ไทย\n- türkçe\n- українська\n- اردو\n- tiếng việt\n- 粵語\n- 中文\nedit links\ncoordinates: 41°43′32″n 49°56′49″w / 41.72556°n 49.94694°w / 41.72556; -49.94694\nfrom wikipedia, the free encyclopedia\n2023 submersible implosion in the atlantic\n|date||18 june 2023|\n|location||north atlantic ocean, near the wreck of the titanic|\n|coordinates||41°43′32″n 49°56′49″w / 41.72556°n 49.94694°w / 41.72556; -49.94694|\n|type||maritime disaster|\n|cause||failure of the pressure hull|\n|participants||5 passengers|\n|outcome||submersible destroyed by implosion|\n|deaths||5 (see fatalities)|\non 18 june 2023, titan, a submersible operated by american tourism and expeditions company oceangate, imploded during an expedition to view the wreck of the titanic in the north atlantic ocean off the coast of newfoundland, canada.on board titan, a submersible operated by american tourism and expeditions company oceangate, were stockton rush, the ceo of american tourism and expeditions company oceangate; paul-henri nargeolet, a french deep sea explorer and the titanic| expert; hamish harding, a british billionaire businessman; shahzada dawood, a pakistani-british billionaire businessman; and dawood's son suleman.communication with titan, a submersible operated by american tourism and expeditions company oceangate, was lost 1 hour and 45 minutes into imploded submersible operated by american tourism and expeditions company oceangate, dive.authorities were alerted when titan, a submersible operated by american tourism and expeditions company oceangate, failed to resurface at the scheduled time later that day.after titan, a submersible operated by american tourism and expeditions company oceangate, had been missing for four days, a remotely operated underwater vehicle (rov) discovered a debris field containing parts of titan, a submersible operated by american tourism and expeditions company oceangate,, about 500 metres (1,600 ft) from the bow of the titanic|.the search area was informed by the united states navy's (usn)"
```

```
"".join(splitter.split_text(text)) == text
    False
```

Additional characters are added
```
len("".join(splitter.split_text(text)))
    2534
len(text)
    2426
```

Newlines are stripped
```
text[:50]
    '- afrikaans\n- العربية\n- azərbaycanca\n- বাংলা\n- бел'
splitter.split_text(text)[0][:50]
    '- afrikaans - العربية - azərbaycanca - বাংলা - бел'
```

Special tokens are added
```
text[193:293]
    'awa\n- kurdî\n- latviešu\n- lietuvių\n- македонски\n- malti\n- मराठी\n- مصرى\n- bahasa melayu\n- nederlands\n-'
"".join(splitter.split_text(text))[200:300]
    'awa - kurdi - latviesu - lietuviu - македонски -malti - [UNK] - مصرى - bahasa melayu - nederlands - '
```


Recommended improvement: call
`tokenizer(text, return_offsets_mapping=True)`

 This will allow selection of N tokens and allow reconstruction without the need for and allow reconstruction without the use of tokenizer.decode (which is not perfectly invertible).

### Who can help?

_No response_

### Information

- [ ] The official example notebooks/scripts
- [X] My own modified scripts

### Related Components

- [ ] LLMs/Chat Models
- [X] Embedding Models
- [ ] Prompts / Prompt Templates / Prompt Selectors
- [ ] Output Parsers
- [X] Document Loaders
- [ ] Vector Stores / Retrievers
- [ ] Memory
- [ ] Agents / Agent Executors
- [ ] Tools / Toolkits
- [ ] Chains
- [ ] Callbacks/Tracing
- [ ] Async

### Reproduction

Please see my code above

### Expected behavior

Please see my code above