ci: Add typos check for common spelling errors. (#492)

This will fail until #490 and #491 land.

I'm not thrilled about the discoverability here if a CI check fails due
to this. We don't really have a place for docs about this yet (even a
`CONTRIBUTING.md`) ...

---------

Co-authored-by: Kaur Kuut <[email protected]>

.github/workflows/ci.yml

@@ -290,3 +290,12 @@ jobs:
       # We test documentation using nightly to match docs.rs. This prevents potential breakages
       - name: cargo doc
         run: cargo doc --workspace --locked --all-features --no-deps --document-private-items -Zunstable-options -Zrustdoc-scrape-examples
+
+  # If this fails, consider changing your text or adding something to .typos.toml
+  typos:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: check typos
+        uses: crate-ci/[email protected]

.typos.toml

@@ -0,0 +1,11 @@
+# See the configuration reference at
+# https://github.com/crate-ci/typos/blob/master/docs/reference.md
+
+# Corrections take the form of a key/value pair. The key is the incorrect word
+# and the value is the correct word. If the key and value are the same, the
+# word is treated as always correct. If the value is an empty string, the word
+# is treated as always incorrect.
+
+# Match Inside a Word - Case Insensitive
+[default.extend-words]
+thm = "thm"