Distribution Wizard typos and some wording issue

As far as I understand, this is a translation default value issue only:

• Step 4: ##platform.extension.distributionWizard.flavorStepCurrentFlavorHint##
• Step 6: ##platform.extension.distributionWizard.flavorStepConfirm##
• Step 8: ##platform.extension.distributionWizard.reportStepDocumentsDescription##

For all three of those keys, the source value should be fixed, but I doubt translations convey those typos/phrasing errors.

Thanks for the in depth description!
The improvements have been proposed in https://github.com/xwiki/xwiki-platform/pull/4643