📝🎨 Mark versions as known word spellings

Otherwise, `sphinxcontrib.spelling` would complain about `dev` and
two/three-letter local version identifier segments as misspelled[[1]].

[1]: sphinx-contrib/spelling#224

docs/conf.py

@@ -37,16 +37,10 @@
     'sphinx_tabs.tabs',
     'sphinxcontrib.apidoc',
     'sphinxcontrib.towncrier.ext',  # provides `.. towncrier-draft-entries::`
-]
 
-# Conditional third-party extensions:
-try:
-    import sphinxcontrib.spelling as _sphinxcontrib_spelling
-except ImportError:
-    extensions.append('spelling_stub_ext')
-else:
-    del _sphinxcontrib_spelling  # noqa: WPS100
-    extensions.append('sphinxcontrib.spelling')
+    # In-tree extensions:
+    'spelling_stub_ext',  # auto-loads `sphinxcontrib.spelling` if installed
+]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']

docs/spelling_stub_ext.py

@@ -3,11 +3,54 @@
 from typing import List
 
 from sphinx.application import Sphinx
+from sphinx.config import Config as _SphinxConfig
+from sphinx.util import logging
 from sphinx.util.docutils import SphinxDirective
 from sphinx.util.nodes import nodes
 
 from cheroot import __version__
 
+try:
+    from enchant.tokenize import (  # noqa: WPS433
+        Filter as _EnchantTokenizeFilterBase,
+    )
+except ImportError:
+    _EnchantTokenizeFilterBase = object  # noqa: WPS440
+
+
+logger = logging.getLogger(__name__)
+
+
+def _configure_spelling_ext(app: Sphinx, config: _SphinxConfig) -> None:
+    class VersionFilter(_EnchantTokenizeFilterBase):  # noqa: WPS431
+        # NOTE: It's nested because we need to reference the config by closure.
+        """Filter for treating version words as known."""
+
+        def _skip(self, word: str) -> bool:
+            # NOTE: Only accessing the config values in the method since they
+            # NOTE: aren't yet populated when the config-inited event happens.
+            known_version_words = {
+                config.release,
+                config.version,
+                __version__,
+            }
+            if word not in known_version_words:
+                return False
+
+            logger.debug(
+                'Known version words: %r',  # noqa: WPS323
+                known_version_words,
+            )
+            logger.debug(
+                'Ignoring %r because it is a known version',  # noqa: WPS323
+                word,
+            )
+
+            return True
+
+    app.config.spelling_filters = [VersionFilter]
+    app.setup_extension('sphinxcontrib.spelling')
+
 
 class SpellingNoOpDirective(SphinxDirective):
     """Definition of the stub spelling directive."""
@@ -21,7 +64,10 @@ def run(self) -> List[nodes.Node]:
 
 def setup(app: Sphinx) -> None:
     """Initialize the extension."""
-    app.add_directive('spelling', SpellingNoOpDirective)
+    if _EnchantTokenizeFilterBase is object:
+        app.add_directive('spelling', SpellingNoOpDirective)
+    else:
+        app.connect('config-inited', _configure_spelling_ext)
 
     return {
         'parallel_read_safe': True,