Change typing.Optional[type] to type | None in docstrings

Also improved docs for *colour* parameter of `PdfPage.render_base()`

src/pypdfium2/_helpers/document.py

@@ -152,7 +152,7 @@ def close(self):
     def get_version(self):
         """
         Returns:
-            typing.Optional[int]: The PDF version of the document (14 for 1.4, 15 for 1.5, ...),
+            int | None: The PDF version of the document (14 for 1.4, 15 for 1.5, ...),
             or :data:`None` if the version could not be determined (e. g. because the document was created using :meth:`PdfDocument.new`).
         """
         version = ctypes.c_int()
@@ -170,7 +170,7 @@ def save(self, buffer, version=None):
             buffer (typing.BinaryIO):
                 A byte buffer to capture the data.
                 It may be any object implementing the ``write()`` method.
-            version (typing.Optional[int]):
+            version (int | None):
                  The PDF version to use, given as an integer (14 for 1.4, 15 for 1.5, ...).
                  If :data:`None`, PDFium will set a version automatically.
         """
@@ -202,7 +202,7 @@ def new_page(self, width, height, index=None):
                 Target page width (horizontal size).
             height (float):
                 Target page height (vertical size).
-            index (typing.Optional[int]):
+            index (int | None):
                 Suggested zero-based index at which the page will be inserted.
                 If *index* is less or equal to zero, the page will be inserted at the beginning.
                 If *index* is :data:`None` or larger that the document's current last index, the page will be appended to the end.
@@ -394,7 +394,7 @@ def _render_base(
         The order of results matches the order of given page indices.
         
         Parameters:
-            page_indices (typing.Optional[typing.Sequence[int]]):
+            page_indices (typing.Sequence[int] | None):
                 A sequence of zero-based indices of the pages to render.
                 If :data:`None`, all pages will be included.
             n_processes (int):

src/pypdfium2/_helpers/misc.py

@@ -50,7 +50,7 @@ class OutlineItem:
             String of the bookmark.
         is_closed (bool):
             If :data:`True`, child items shall be hidden by default.
-        page_index (int):
+        page_index (int | None):
             Zero-based index of the page the bookmark points to.
         view_mode (int):
             A view mode constant (``PDFDEST_VIEW_...``) defining how the coordinates of *view_pos* shall be interpreted.

src/pypdfium2/_helpers/page.py

@@ -276,11 +276,13 @@ def render_base(
                 Amount in PDF canvas units to cut off from page borders (left, bottom, right, top).
                 Crop is applied after rotation.
             
-            colour (typing.Optional[ typing.Tuple[int, int, int, typing.Optional[int]] ]):
+            colour (typing.Tuple[int, int, int, int] | typing.Tuple[int, int, int] | None):
                 Page background colour. Defaults to white.
-                It can either be :data:`None`, or values of red, green, blue, and alpha ranging from 0 to 255.
                 If :data:`None`, the bitmap will not be filled with a colour, resulting in transparent background.
-                For RGB, 0 will include nothing of the colour in question, while 255 will completely include it. For Alpha, 0 means full transparency, while 255 means no transparency.
+                Otherwise, *colour* shall be a list of values for red, green, blue, and optionally alpha, ranging from 0 to 255.
+                If alpha is not given, it defaults to 255.
+                For RGB, 0 will include nothing of the colour in question, while 255 will fully include it.
+                For Alpha, 0 means full transparency, while 255 means no transparency.
             
             annotations (bool):
                 Whether to render page annotations.
@@ -295,7 +297,7 @@ def render_base(
                 A list of item types that shall not be smoothed (text, image, path).
         
         Returns:
-            (ctypes.c_ubyte_Array_N, str, (int, int)):
+            (``ctypes.c_ubyte_Array_%d``, str, (int, int)):
             Ctypes array, colour format, and image size.
             The colour format can be ``BGRA``, ``BGR``, or ``L``, depending on the parameters *colour* and *greyscale*.
             Image size is given in pixels as a tuple of width and height.

src/pypdfium2/_helpers/textpage.py

@@ -100,7 +100,7 @@ def get_index(self, x, y, x_tol, y_tol):
             y_tol (float): Vertical tolerance.
         
         Returns:
-            typing.Optional[int]: The index of the character at or nearby the point (x, y).
+            int | None: The index of the character at or nearby the point (x, y).
             May be :data:`None` if there is no character or an error occurred.
         """
         index = pdfium.FPDFText_GetCharIndexAtPos(self._textpage, x, y, x_tol, y_tol)