[cleanup] Fix W504 error in scripts/welcome.py
[cleanup] Fix W504 error in scripts/welcome.py

Fixed breaking of line after a binary operator. So the line
break should happen before it with the line wrapped in parentheses.

In case the operator falls on the same line with the next line, do
1 more 4 spaces indentation. This patch does that!

Bug: T207836
Depends-On: I203077c45b6fba00502e3e8c536da5a049493acd
Change-Id: Iac640afd147ce3d100bd23560f5a5c8087b467c1

wikimedia/pywikibot-core,wikimedia/pywikibot-core,PersianWikipedia/pywikibot-core