generate: Add signal emitter attribute

docs/attributes.rst

@@ -26,6 +26,10 @@ The following attributes apply to methods of a classed type or interface.
   Defines the property set by the function. The property name must be in
   the same type as the method
 
-``out.gtk.Method.get_property`` = ``s``
+``org.gtk.Method.get_property`` = ``s``
   Defines the property retrieved by the function. The property name must
   be in the same type as the method
+
+``org.gtk.Method.signal`` = ``s``
+  Defines the signal emitted by the function. The signal name must be
+  in the same type as the method

gidocgen/gdgenerate.py

@@ -512,6 +512,11 @@ class TemplateMethod:
             href = f"property.{type_.name}.{value}.html"
             return Markup(f"<a href=\"{href}\"><code>{text}</code></a>")
 
+        def transform_signal_attribute(namespace, type_, method, value):
+            text = f"{namespace.name}.{type_.name}::{value}"
+            href = f"signal.{type_.name}.{value}.html"
+            return Markup(f"<a href=\"{href}\"><code>{text}</code></a>")
+
         ATTRIBUTE_NAMES = {
             "org.gtk.Method.set_property": {
                 "label": "Sets property",
@@ -520,6 +525,10 @@ class TemplateMethod:
             "org.gtk.Method.get_property": {
                 "label": "Gets property",
                 "transform": transform_property_attribute,
+            },
+            "org.gtk.Method.signal": {
+                "label": "Emits signal",
+                "transform": transform_signal_attribute,
             }
         }