Add a missing colon at the end of the expected panic message in location-detail-unwrap-multiline.rs

Author: dpaoliello

tests/ui/panics/location-detail-unwrap-multiline.rs

@@ -1,7 +1,7 @@
 //@ run-fail
 //@ compile-flags: -Cstrip=none -Cdebuginfo=line-tables-only -Copt-level=0
 //@ exec-env:RUST_BACKTRACE=1
-//@ regex-error-pattern: location-detail-unwrap-multiline\.rs:11(:10)?\n
+//@ regex-error-pattern: location-detail-unwrap-multiline\.rs:11(:10)?:\n
 //@ needs-unwind
 //@ ignore-android FIXME #17520