Add 'Module resolution' section

Author: not-my-profile

node/npm_specifiers.md

@@ -48,6 +48,32 @@ package:
 import express from "npm:express@^4.17";
 ```
 
+### Module resolution
+
+The official TypeScript compiler `tsc` supports different
+[moduleResolution](https://www.typescriptlang.org/tsconfig#moduleResolution)
+settings. Deno only supports the modern `node16` resolution. Unfortunately many
+NPM packages fail to correctly provide types under node16 module resolution,
+which can result in `deno check` reporting type errors, that `tsc` does not
+report.
+
+If a default export from an `npm:` import appears to have a wrong type (with the
+right type seemingly being available under the `.default` property), it's most
+likely that the packaged types do not support node16. You can verify this by
+checking if the error also occurs with `tsc --module node16` or by consulting
+the [Are the types wrong?](https://arethetypeswrong.github.io/) website
+(particularly the "node16 from ESM" row).
+
+If you want to use a package that doesn't support TypeScript's node16 module
+resolution, you can:
+
+1. Open an issue at the issue tracker of the package about the problem. (And
+   perhaps contribute a fix :)
+2. Use a [CDN](./cdns.md), that rebuilds the packages for Deno support, instead
+   of an `npm:` identifier.
+3. Ignore the type errors you get in your code base with `// @ts-expect-error`
+   or `// @ts-ignore`.
+
 ### Including Node types
 
 Node ships with many built-in types like `Buffer` that might be referenced in an