Fix one docs link and resolve some warnings for two others (#7153)

Author: dmontagu

docs/migration.md

@@ -786,7 +786,8 @@ class Model(BaseModel):
     x: MyInt
 ```
 
-Read more about it on the [Composing types via `Annotated`](../usage/types/custom/#composing-types-via-annotated) section.
+Read more about it in the [Composing types via `Annotated`](./usage/types/custom.md#composing-types-via-annotated)
+docs.
 
 For `ConstrainedStr` you can use [`StringConstraints`][pydantic.types.StringConstraints] instead.
 
@@ -802,7 +803,7 @@ For `ConstrainedStr` you can use [`StringConstraints`][pydantic.types.StringCons
 | `pydantic.error_wrappers.ValidationError` | `pydantic.ValidationError` |
 | `pydantic.utils.to_camel` | `pydantic.alias_generators.to_pascal` |
 | `pydantic.utils.to_lower_camel` | `pydantic.alias_generators.to_camel` |
-| `pydantic.PyObject` | [`pydantic.ImportString`](usage/types/string_types/#importstring) |
+| `pydantic.PyObject` | [`pydantic.ImportString`](usage/types/string_types.md#importstring) |
 
 ## Deprecated and moved in Pydantic V2
 

docs/usage/dataclasses.md

@@ -138,7 +138,7 @@ class MyDataclass2:
 1. You can read more about `validate_assignment` in [model_config](model_config.md#validate-assignment).
 
 !!! note
-    Pydantic dataclasses do not support [`extra='allow'`](model_config/#extra-attributes), where extra fields passed
+    Pydantic dataclasses do not support [`extra='allow'`](model_config.md#extra-attributes), where extra fields passed
     to the initializer would be stored as extra attributes on the dataclass.
 
     `extra='ignore'` is still supported for the purpose of ignoring