Added support for alternative parameter names

Fixes #144.

Author: agronholm

CHANGELOG.rst

@@ -2,6 +2,7 @@ UNRELEASED
 ==========
 
 * Dropped support for Sphinx < 3.0
+* Added support for alternative parameter names (``arg``, ``argument``, ``parameter``)
 * Fixed ``TypeError`` when formatting a parametrized ``typing.IO`` annotation
 * Fixed data class displaying a return type in its ``__init__()`` method
 

sphinx_autodoc_typehints.py

@@ -372,16 +372,17 @@ def process_docstring(app, what, name, obj, options, lines):
             formatted_annotation = format_annotation(
                 annotation, fully_qualified=app.config.typehints_fully_qualified)
 
-            searchfor = ':param {}:'.format(argname)
+            searchfor = [':{} {}:'.format(field, argname)
+                         for field in ('param', 'parameter', 'arg', 'argument')]
             insert_index = None
 
             for i, line in enumerate(lines):
-                if line.startswith(searchfor):
+                if any(line.startswith(search_string) for search_string in searchfor):
                     insert_index = i
                     break
 
             if insert_index is None and app.config.always_document_param_types:
-                lines.append(searchfor)
+                lines.append(':param {}:'.format(argname))
                 insert_index = len(lines)
 
             if insert_index is not None:

tests/roots/test-dummy/dummy_module.py

@@ -142,7 +142,7 @@ def function_with_unresolvable_annotation(x: 'a.b.c'):  # noqa: F821
     """
     Function docstring.
 
-    :param x: foo
+    :arg x: foo
     """
 
 
@@ -154,7 +154,7 @@ def function_with_typehint_comment(
     """
     Function docstring.
 
-    :param x: foo
+    :parameter x: foo
     :param y: bar
     """
 
@@ -181,7 +181,7 @@ def foo(
         """
         Method docstring.
 
-        :param x: foo
+        :arg x: foo
         """
         return 42
 
@@ -191,10 +191,10 @@ def function_with_typehint_comment_not_inline(x=None, *y, z, **kwargs):
     """
     Function docstring.
 
-    :param x: foo
-    :param y: bar
-    :param z: baz
-    :param kwargs: some kwargs
+    :arg x: foo
+    :argument y: bar
+    :parameter z: baz
+    :parameter kwargs: some kwargs
     """