Merge pull request #493 from github/aeisenberg/contributing2

Fix information about `npm ci`

CONTRIBUTING.md

@@ -26,9 +26,9 @@ You may want to run `tsc --watch` from the command line or inside of vscode in o
 
 ### Checking in compiled artifacts and `node_modules`
 
-Because CodeQL Action users consume the code directly from this repository, and there can be no build step during an GitHub Actions run, this repository contains all compiled artifacts and node modules. There is a PR check that will fail if any of the compiled artifacts are not up to date. Compiled artifacts are stored in the `lib/` folder. For all day-to-day development purposes, this folder can be ignored.
+Because CodeQL Action users consume the code directly from this repository, and there can be no build step during an GitHub Actions run, this repository contains all compiled artifacts and node modules. There is a PR check that will fail if any of the compiled artifacts are not up to date. Compiled artifacts are stored in the `lib/` directory. For all day-to-day development purposes, this folder can be ignored.
 
-Avoid running `npm install` (the node moddules should be up to date when you check out anyway) and instead use `npm ci` when you want to update dependencies `package.json`. If you make any changes to the `node_modules` folder , you must run `npm run removeNPMAbsolutePaths` to clean the folder and remove any locally identifying data. There is a PR check to ensure that this command has been run.
+Only run `npm install` if you are explicitly changing the set of dependencies in `package.json`. The `node_modules` directory should be up to date when you check out, but if for some reason, there is an inconsistency use `npm ci && npm run removeNPMAbsolutePaths` to ensure the directory is in a state consistent with the `package-lock.json`. There is a PR check to ensure the consistency of the `node_modules` directory.
 
 ### Running the action