Add codespell CI for spell checking documentation

- Add GitHub Actions workflow for codespell
- Configure codespell in pyproject.toml
- Skip submodules and build output (they have their own checks)

Author: neuromechanist

.github/workflows/codespell.yml

@@ -0,0 +1,25 @@
+# Codespell configuration is within pyproject.toml
+---
+name: Codespell
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+jobs:
+  codespell:
+    name: Check for spelling errors
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Annotate locations with typos
+        uses: codespell-project/codespell-problem-matcher@v1
+      - name: Codespell
+        uses: codespell-project/actions-codespell@v2

pyproject.toml

@@ -60,3 +60,9 @@ target-version = "py311"
 [tool.ruff.lint]
 select = ["E", "W", "F", "I", "B", "UP"]
 ignore = ["E501"]
+
+[tool.codespell]
+# Ref: https://github.com/codespell-project/codespell#using-a-config-file
+skip = '.git*,*.svg,site/*,hedit/*,image-annotation/*'
+check-hidden = true
+# ignore-words-list = ''