Add Type Adapter Docs example codes & information about dump_json() (p…

…ydantic#9477)

Co-authored-by: Sydney Runkle <54324534+sydney-runkle@users.noreply.github.com>

docs/concepts/type_adapter.md

@@ -26,7 +26,8 @@ class User(TypedDict):
 
 
 user_list_adapter = TypeAdapter(List[User])
-print(repr(user_list_adapter.validate_python([{'name': 'Fred', 'id': '3'}])))
+user_list = user_list_adapter.validate_python([{'name': 'Fred', 'id': '3'}])
+print(repr(user_list))
 #> [{'name': 'Fred', 'id': 3}]
 
 try:
@@ -40,8 +41,17 @@ except ValidationError as e:
     0.id
       Input should be a valid integer, unable to parse string as an integer [type=int_parsing, input_value='wrong', input_type=str]
     """
+
+print(repr(user_list_adapter.dump_json(user_list)))
+#> b'[{"name":"Fred","id":3}]'
 ```
 
+!!! info "`dump_json` returns `bytes`"
+    `TypeAdapter`'s `dump_json` methods returns a `bytes` object, unlike the corresponding method for `BaseModel`, `model_dump_json`, which returns a `str`.
+    The reason for this discrepancy is that in V1, model dumping returned a str type, so this behavior is retained in V2 for backwards compatibility.
+    For the `BaseModel` case, `bytes` are coerced to `str` types, but `bytes` are often the desired end type.
+    Hence, for the new `TypeAdapter` class in V2, the return type is simply `bytes`, which can easily be coerced to a `str` type if desired.
+
 !!! note
     Despite some overlap in use cases with [`RootModel`][pydantic.root_model.RootModel],
     [`TypeAdapter`][pydantic.type_adapter.TypeAdapter] should not be used as a type annotation for