Attempt to fix readthedocs build config

.readthedocs.yaml

@@ -1,10 +1,9 @@
 version: 2
 sphinx:
    configuration: docs/conf.py
-build:
-  os: "ubuntu-22.04"
-  tools:
-    python: "3.10"
-  jobs:
-    post_create_environment:
-      - cd docs && pip install --exists-action=w --no-cache-dir -r requirements.txt
+python:
+  version: "3.10"
+  install:
+    - method: pip
+      path: ./src/
+    - requirements: docs/requirements.rtd.txt

doc/requirements.rtd.txt

@@ -0,0 +1,10 @@
+sphinx==2.3.*
+jinja2==3.0.*
+sphinx-rtd-theme
+sphinxcontrib-httpdomain
+sphinxcontrib-images
+sphinxcontrib-spelling==4.*
+sphinxemoji
+pygments-markdown-lexer
+# See https://github.com/rfk/pyenchant/pull/130
+git+https://github.com/raphaelm/pyenchant.git@patch-1#egg=pyenchant