Added better docs; added PRNGKeys. Packaging with pyproject.toml.

Also added support for matching dtypes using regexes, and for nesting e.g. Shaped[Float[Array, "dim1 dim2"], "dim3"].

.github/workflows/build_docs.yml

@@ -0,0 +1,39 @@
+name: Build docs
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        python-version: [ 3.11 ]
+        os: [ ubuntu-latest ]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install .
+          python -m pip install -r docs/requirements.txt
+
+      - name: Build docs
+        run: |
+          mkdocs build
+          mkdocs build  # twice, see https://github.com/patrick-kidger/pytkdocs_tweaks
+
+      - name: Upload docs
+        uses: actions/upload-artifact@v2
+        with:
+          name: docs
+          path: site  # where `mkdocs build` puts the built site