portico: Make minor fixes in Lean case study.
portico: Make minor fixes in Lean case study.

zulip/zulip,zulip/zulip,kou/zulip,rht/zulip,rht/zulip,andersk/zulip,andersk/zulip,andersk/zulip,kou/zulip,rht/zulip,kou/zulip,zulip/zulip,kou/zulip,zulip/zulip,andersk/zulip,zulip/zulip,kou/zulip,rht/zulip,kou/zulip,rht/zulip,andersk/zulip,andersk/zulip,kou/zulip,zulip/zulip,zulip/zulip,rht/zulip,rht/zulip,andersk/zulip