Adding full dist directory to package.json exports.

[joeldenning]

Without this, you can't use any of the extras in NodeJS.

Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './dist/extras/amd.js' is not defined by "exports" in /Users/joeldenning/code/isomorphic-root-config/node_modules/systemjs/package.json

I considered remapping so that the dist was not necessary in import paths. But I think that would be a breaking change since some people are already doing import 'systemjs/dist/system.js' (at least in webpack bundles) and have the dist in their code.

[github-actions]

core

File by file impact

Pull request have no impact on core files.

extras

File by file impact

Pull request have no impact on extras files.

_{Generated by github pull request filesize impact}

[guybedford]

The general rule to consider with path exports is that every file exposed should be an entry point or source map / asset used by an entry point. This meets that criteria fine so seems good.