No longer forcibly echo off during windows batch activation

[wiktorinox]

During fixing of #2728 new issue has been introduced.
Adding echo off at the beginning of the activate.bat cause this setting to persist after activation.
It doesn't occur when activated in the interactive shell, but it does when activating inside of the Windows batch script - incidentaly that's how Jenkins bat step executes it's contents.
This behaviour is unexpected and activation should not force specific echo on/off setting.

This change removes that echo off while still fixing #2728 - no additional parentheses are displayed when activating in windows batch.

I would love to write tests for that but I have no idea how - the way current tests are written is pretty convoluted and I don't understand them. However, I hope that this change is small enough that tests won't be necessary.

Thanks for contributing, make sure you address all the checklists (for details on how see development documentation)

• ran the linter to address style issues (tox -e fix)
• wrote descriptive pull request text
• ensured there are test(s) validating the fix
• added news fragment in docs/changelog folder
• updated/extended the documentation

[gaborbernat]

Test please.

[wiktorinox]

@gaborbernat Like I wrote in the PR - I don't understand how to write the tests in this repository. If you could advise what's the execution flow and what parts are necessary for the test and where the assertions should live, then I would be able to write the tests.

For example for the test for this functionality I need to be able to create a bat file that will contain invocation of activate.bat and then observe output - is that even possible in your framework?

[gaborbernat]

Yes, and you'll see example of if in the test suite.

[wiktorinox]

I've added a test for this case.

The merge-base changed after approval.