Highlight-regexp does not work in REPL buffer

[clyfe]

Expected behavior

When I M-x: highlight-regexp a word in the REPL buffer, I expect it to show up highlighted. hi-lock-mode is enabled.

Actual behavior

The word is not highlighted.

Steps to reproduce the problem

1. Output something in the REPL buffer.
2. M-x highlight-regexp and type a word from the buffer.
3. The word is now still not highlighted.

Environment & Version information

CIDER version information

;; CIDER 1.20.0 (Lanzarote), nREPL 1.5.1
;; Clojure 1.12.0, Java 21.0.9

Lein / Clojure CLI version

Clojure CLI version 1.12.0.1479

Emacs version

30.2

Operating system

Ubuntu 24.04

JDK distribution

openjdk version "21.0.9" 2025-10-21

[bbatsov]

Related to #3787

[github-actions]

This issue has been automatically marked as stale because it has not had any recent activity. It will be closed soon if no further activity occurs. Thank you for your contribution and understanding!