GHA: fix escaping in codespell job

Also ignore 'copyIn' method with codespell circa Debian 13.

Author: mdavidsaver

.ci-local/codespell.dic

@@ -1,3 +1,4 @@
 als
 SLAC
 slac
+copyIn

.github/workflows/codespell.yml

@@ -27,4 +27,4 @@ jobs:
         sudo apt-get update
         sudo apt-get -y install codespell
     - name: codespell
-      run: git ls-files | grep -vE 'test|bundle|.ci|.\db' | xargs codespell -I .ci-local/codespell.dic
+      run: git ls-files | grep -vE 'test|bundle|\.ci|\.db' | xargs codespell -I .ci-local/codespell.dic