feat: Add option to show type annotations in signatures

Issue: #106

docs/handlers/python.md

@@ -71,19 +71,11 @@ Option | Type | Description | Default
 
 ### Rendering
 
-These options affect how the documentation is rendered.
+::: mkdocstrings.handlers.python:PythonRenderer.default_config
+    rendering:
+      show_root_toc_entry: false
 
-Option | Type | Description | Default
------- | ---- | ----------- | -------
-**`show_root_heading`** | `bool` | Show the heading of the object at the root of the documentation tree. | `False`
-**`show_root_toc_entry`** | `bool` | If the root heading is not shown, at least add a ToC entry for it. | `True`
-**`show_root_full_path`** | `bool` | Show the full Python path for the root object heading. | `True`
-**`show_object_full_path`** | `bool` | Show the full Python path of every object. | `False`
-**`show_category_heading`** | `bool` | When grouped by categories, show a heading for each category. | `False`
-**`show_if_no_docstring`** | `bool` | Show the object heading even if it has no docstring or children with docstrings. | `False`
-**`show_source`** | `bool` | Show the source code of this object. | `True`
-**`group_by_category`** | `bool` | Group the object's children by categories: attributes, classes, functions, methods, and modules. | `True`
-**`heading_level`** | `int` | The initial heading level to use. | `2`
+These options affect how the documentation is rendered.
 
 !!! example "Configuration example"
     === "Global"

src/mkdocstrings/handlers/python.py

@@ -43,6 +43,7 @@ class PythonRenderer(BaseRenderer):
         "show_object_full_path": False,
         "show_category_heading": False,
         "show_if_no_docstring": False,
+        "show_signature_annotations": False,
         "show_source": True,
         "group_by_category": True,
         "heading_level": 2,
@@ -59,6 +60,7 @@ class PythonRenderer(BaseRenderer):
     **`show_root_members_full_path`** | `bool` | Show the full Python path of objects that are children of the root object (for example, classes in a module). When False, `show_object_full_path` overrides. | `False`
     **`show_category_heading`** | `bool` | When grouped by categories, show a heading for each category. | `False`
     **`show_if_no_docstring`** | `bool` | Show the object heading even if it has no docstring or children with docstrings. | `False`
+    **`show_signature_annotations`** | `bool` | Show the type annotations in methods and functions signatures. | `False`
     **`show_source`** | `bool` | Show the source code of this object. | `True`
     **`group_by_category`** | `bool` | Group the object's children by categories: attributes, classes, functions, methods, and modules. | `True`
     **`heading_level`** | `int` | The initial heading level to use. | `2`

src/mkdocstrings/references.py

@@ -28,7 +28,7 @@ class Placeholder:
     substitution again.
     """
 
-    def __init__(self, seed_length=16) -> None:
+    def __init__(self, seed_length: int = 16) -> None:
         """
         Initialize the object.
 
@@ -125,7 +125,7 @@ def relative_url(url_a: str, url_b: str) -> str:
     return f"{relative}#{anchor}"
 
 
-def fix_ref(url_map, from_url, unmapped: List[str]) -> Callable:  # noqa: WPS231 (not that complex)
+def fix_ref(url_map: Dict[str, str], from_url: str, unmapped: List[str]) -> Callable:  # noqa: WPS231 (not that complex)
     """
     Return a `repl` function for [`re.sub`](https://docs.python.org/3/library/re.html#re.sub).
 

src/mkdocstrings/templates/python/material/signature.html

@@ -1,6 +1,10 @@
 {% if signature %}
   {% with %}
-    {% set ns = namespace(render_pos_only_separator=True, render_kw_only_separator=True) %}
+    {% set ns = namespace(render_pos_only_separator=True, render_kw_only_separator=True, equal="=") %}
+
+    {% if config.show_signature_annotations %}
+      {% set ns.equal = " = " %}
+    {% endif %}
 
     ({% for parameter in signature.parameters %}{% if parameter.kind == "POSITIONAL_ONLY" %}
       {% if ns.render_pos_only_separator %}
@@ -9,14 +13,18 @@
         {% if ns.render_kw_only_separator %}
           {% set ns.render_kw_only_separator = False %}*, {% endif %}
       {% endif %}
+      {% if config.show_signature_annotations and "annotation" in parameter %}
+        {% set annotation = ": " + parameter.annotation|safe %}
+      {% endif %}
       {% if "default" in parameter %}
-        {% set default = "=" + parameter.default|safe %}
+        {% set default = ns.equal + parameter.default|safe %}
       {% endif %}
       {% if parameter.kind == "VAR_POSITIONAL" %}*
         {% set render_kw_only_separator = False %}
       {% elif parameter.kind == "VAR_KEYWORD" %}**
-      {% endif %}{{ parameter.name }}{{ default }}{% if not loop.last %}, {% endif %}
-    {% endfor %})
+      {% endif %}{{ parameter.name }}{{ annotation }}{{ default }}{% if not loop.last %}, {% endif %}
+    {% endfor %}){% if config.show_signature_annotations and "return_annotation" in signature %} -> {{ signature.return_annotation }}
+    {% endif %}
 
   {% endwith %}
 {% endif %}