Add browser sourcemap

[lukastaegert]

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

List any relevant issue numbers:

Description

Apparently people are using the REPL to actually debug Rollup issues. Which is a good thing, therefore this is including specifically the source map of the browser bundle in the package.
Also it removes a left-over log statement.

[rollup-bot]

Thank you for your contribution! ❤️

You can try out this pull request locally by installing Rollup via

npm install rollup/rollup#include-browser-sourcemap

or load it into the REPL:
https://rollupjs.org/repl/?circleci=14492

[codecov]

Codecov Report

Merging #3990 (c0f7ea2) into master (a692a8d) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3990      +/-   ##
==========================================
- Coverage   97.22%   97.22%   -0.01%     
==========================================
  Files         191      191              
  Lines        6732     6731       -1     
  Branches     1970     1970              
==========================================
- Hits         6545     6544       -1     
  Misses         99       99              
  Partials       88       88              

Impacted Files	Coverage Δ
src/Module.ts	100.00% <ø> (ø)

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