Add docstrings for _models/completions/token.py - v1

Author: Mandzhi

src/yandex_cloud_ml_sdk/_models/completions/token.py

@@ -9,8 +9,13 @@
 
 @dataclass(frozen=True)
 class Token:
+    """This class encapsulates the properties of a token
+    and represents it in a text processing context."""
+    #: a unique identifier for the token
     id: int
+    #: a flag indicating if the token is a special one
     special: bool
+    #: the textual representation of the token
     text: str
 
     @classmethod