Fixed buggy format in jinja2 templates
Fixed buggy format in jinja2 templates

Jinja2 filter for "format" only accepts "%s" placeholders, but Pelican has
long moved on to "{slug}" formatting:
https://docs.getpelican.com/en/stable/settings.html#feed-settings

nairobilug/pelican-alchemy,nairobilug/pelican-alchemy