chore(docs): upgrade sphinx

.readthedocs.yaml

@@ -1,13 +1,15 @@
 version: 2
 
 build:
-  os: ubuntu-22.04
+  os: ubuntu-24.04
   tools:
-    python: "3.11"
+    python: "3.14"
 
 sphinx:
    configuration: docs/src/conf.py
 
 python:
    install:
    - requirements: docs/requirements.txt
+   - method: pip
+     path: .

README.rst

@@ -22,7 +22,7 @@ Usage
 The 3x3 augmented affine transformation matrix for transformations in two
 dimensions is illustrated below.
 
-::
+.. code-block:: none
 
   | x' |   | a  b  c | | x |
   | y' | = | d  e  f | | y |

docs/requirements.txt

@@ -1,2 +1,2 @@
 attrs
-sphinx==6.2.1
+sphinx==9.1.0

docs/src/conf.py

@@ -11,7 +11,7 @@
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
 
 project = "rasterio/affine"
-copyright = "2025, Sean Gillies"
+project_copyright = "%Y, Sean Gillies"
 author = "Sean Gillies"
 release = "development"
 
@@ -22,27 +22,18 @@
     "sphinx.ext.autodoc",
     "sphinx.ext.coverage",
     "sphinx.ext.ifconfig",
+    "sphinx.ext.napoleon",  # NumPy doc style.
+    "sphinx.ext.todo",
     "sphinx.ext.viewcode",
-    "sphinx.ext.githubpages",
 ]
 
 templates_path = ["_templates"]
-exclude_patterns = ["Thumbs.db", ".DS_Store"]
-
-# The suffix of source filenames.
-source_suffix = ".rst"
-
-# The root toctree document.
-root_doc = "index"
-
-# The name of the Pygments (syntax highlighting) style to use.
-pygments_style = "sphinx"
+exclude_patterns = ["build", "Thumbs.db", ".DS_Store"]
 
 # -- Options for HTML output -------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#options-for-html-output
 
 html_theme = "nature"
-
 html_static_path = ["_static"]
 
 # If this is not None, a 'Last updated on:' timestamp is inserted at every page bottom.

src/affine/__init__.py

@@ -89,15 +89,18 @@ class Affine:
 
     Parameters
     ----------
-    a, b, c, d, e, f, [g, h, i] : float
-        Coefficients of the 3 x 3 augmented affine transformation
-        matrix.
+    a, b, c, d, e, f : float
+        Coefficients of the 3 x 3 augmented affine transformation matrix.
+
+    g, h, i : float, optional
+        Coefficients of the 3 x 3 augmented affine transformation matrix.
 
     Attributes
     ----------
     a, b, c, d, e, f, g, h, i : float
-        Coefficients of the 3 x 3 augmented affine transformation
-        matrix::
+        Coefficients of the 3 x 3 augmented affine transformation matrix.
+
+        .. code-block:: none
 
             | x' |   | a  b  c | | x |
             | y' | = | d  e  f | | y |