pre-commit: disable shellcheck for zsh files

`shellcheck` does not support zsh and throws all sort of errors because
the pre-commit thinks all zsh file are shell scripts.

.pre-commit-config.yaml

@@ -1,4 +1,7 @@
 repos:
+- repo: meta
+  hooks:
+  - id: check-useless-excludes
 - repo: https://github.com/pre-commit/pre-commit-hooks
   rev: v4.6.0
   hooks:
@@ -13,3 +16,8 @@ repos:
   rev: v0.10.0.1
   hooks:
   - id: shellcheck
+    exclude: |
+      (?x)^(
+        config\/zsh\/.*|
+        home/\.zshenv
+      )$