Swift: add shared/** to CI triggers

Not being triggered by changes in shared was making it possible to not
notice changes in `shared` having effect on Swift tests. For example
[this PR](https://github.com/github/codeql/pull/15501) introduced a
test change that was fixed [here](https://github.com/github/codeql/pull/16197).

.github/workflows/swift.yml

@@ -6,6 +6,7 @@ on:
       - "swift/**"
       - "misc/bazel/**"
       - "misc/codegen/**"
+      - "shared/**"
       - "*.bazel*"
       - .github/workflows/swift.yml
       - .github/actions/**
@@ -22,10 +23,12 @@ on:
       - "swift/**"
       - "misc/bazel/**"
       - "misc/codegen/**"
+      - "shared/**"
       - "*.bazel*"
       - .github/workflows/swift.yml
       - .github/actions/**
       - codeql-workspace.yml
+      - .pre-commit-config.yaml
       - "!**/*.md"
       - "!**/*.qhelp"
     branches: