doc: require hawkmoth for the documentation build

Now that we have documentation deployed at GitHub Pages, and we no
longer have to rely on Clang being available at Read The Docs in the
future, require Hawkmoth for the documentation build.

The fallback automock has not been updated in ages, and the
documentation build doesn't even work properly with that anymore. Just
throw it out.

doc/conf.py

@@ -17,6 +17,9 @@
 sys.path.insert(0, os.path.abspath('..'))
 
 extensions = [
+    'hawkmoth',
+    'hawkmoth.ext.javadoc',
+    'hawkmoth.ext.napoleon',
     'sphinx.ext.intersphinx',
 ]
 
@@ -39,33 +42,12 @@
 # that this is not the same as Hawkmoth extension minimum version requirement.
 needs_sphinx = '4.4'
 
-# Add any Sphinx extension module names here, as strings. They can be
-# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
-# ones.
-
-# Handle failing hawkmoth import gracefully to be able to build the
-# documentation on e.g. https://readthedocs.org/ which would otherwise fail due
-# to missing clang.
-
-# This is not a good example to follow in regular documentation.
-try:
-    import hawkmoth
+# Setup Clang on Read The Docs
+if 'READTHEDOCS' in os.environ:
     from hawkmoth.util import readthedocs
 
     readthedocs.clang_setup()
 
-    extensions.append('hawkmoth')
-    extensions.append('hawkmoth.ext.napoleon')
-    extensions.append('hawkmoth.ext.javadoc')
-    tags.add('have_hawkmoth')
-
-except ImportError:
-    sys.stderr.write('Warning: Failed to import hawkmoth. Mocking results.\n')
-    sys.path.insert(0, os.path.abspath('ext'))
-    # The mock extension will include the hawkmoth test suite expected results
-    # into the documentation instead of generating.
-    extensions.append('automock')
-
 hawkmoth_root = os.path.join(os.path.abspath(os.path.dirname(__file__)), '../test/examples')
 
 # Add any paths that contain templates here, relative to this directory.

doc/examples.rst

@@ -12,12 +12,6 @@ This page showcases Hawkmoth in action.
    :local:
    :depth: 1
 
-.. only:: not have_hawkmoth
-
-   .. note:: The documentation you are viewing was built without Hawkmoth and/or
-             its dependencies (perhaps on https://readthedocs.org/). The output
-             seen below was pre-generated statically using Hawkmoth, and should
-             closely reflect actual results.
 
 Overview
 --------

test/update-examples.py

@@ -37,12 +37,6 @@ def print_header():
    :local:
    :depth: 1
 
-.. only:: not have_hawkmoth
-
-   .. note:: The documentation you are viewing was built without Hawkmoth and/or
-             its dependencies (perhaps on https://readthedocs.org/). The output
-             seen below was pre-generated statically using Hawkmoth, and should
-             closely reflect actual results.
 ''')
 
 def print_title(testcases):