Console text to search upon:
[echo] ........................
[echo] Conflicts found in merge
[echo] Merge prepared: r136300:136558
[echo] Don't fail. This is a dropmerge
[echo] done.
[echo] ***********************

Used regex:
(Merge (done|prepared): r.*)

Current result: \1
Previous result (in this case): Merge prepared: r136300:136558