Add category input

This adds a section on checking in compiled artifacts.

Update contributing guide

Ran `npm audit fix`.

Even though this fixes a "high" severity vulnerability, all affected
packages are dev packages only.

Make matrix run all cases of the python-deps tests

Co-authored-by: Robert <robertbrignull@github.com>

Fix information about `npm ci`

Fix security vulnerabilities

Output environment file for Windows

This version will count lines of code in each file serially. It still
runs all file system operations asynchronously. The only difference now
is that it will only count one file at a time. It is slower, but it
is able to count large repositories without running out of memory.

This is just a helpful way to ensure you can run `tsc --watch` from
inside vscode.

Update loc count library

Fixes a bug where we were looking for incorrect keys for metrics rules.
Previously, we were using full language names in the keys. Now, we use
the short language names in the metric ids. This is done through a
simplification of the code.

Also, this change does two smaller things:

1. Prints out the baseline count to the logs
2. Adds the `assertNever` function to ensure we never miss a case in
   a switch statement. This function is borrowed from vscode-codeql.

Use the prefix id for keying into metrics rules

Previously, we were always using `**` in the include path. the
effect of this was to always count lines in the entire
repository unless explicitly added to the paths-ignore. This
was incorrect behaviour. Now we only using `**` if the include
path is otherwise empty.

Change include path for lines of code counting

Add a tasks.json

These warnings refer to a hack that was added to the CLI in
github/semmle-code#39335

They can be removed again once the CLI has a more principled way for
the CLI to recognize that it's being invoked by the runner/action.

Add warnings about CLI hack to codeql.ts