Fix typos in CMakeLists

Change-Id: Ieeafecd850b9b18e18596fbe6d41df9ff2944b80
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/38102
Reviewed-by: David Neto <dneto@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>
Commit-Queue: dan sinclair <dsinclair@chromium.org>
diff --git a/.gitignore b/.gitignore
index 9d6a3b1..3805ec5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,8 +4,10 @@
 .gclient_entries
 .vs
 .vscode
+.idea
 build
 buildtools
+cmake-build-*/
 coverage.summary
 lcov.info
 out