assets/gen-regions.js: Cleaner URL encoding
assets/gen-regions.js: Cleaner URL encoding

This escapes ampersand characters from the region string, preventing
parsing errors.

ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.cc,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.cc,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.cc