Update matrix_bot_chatgpt_matrix_blacklist/matrix_bot_chatgpt_matrix_whitelist comment

roles/custom/matrix-bot-chatgpt/defaults/main.yml

@@ -54,6 +54,9 @@ matrix_bot_chatgpt_matrix_default_prefix: "!chatgpt "  # MATRIX_DEFAULT_PREFIX=
 matrix_bot_chatgpt_matrix_default_prefix_reply: false  # MATRIX_DEFAULT_PREFIX_REPLY=
 
 # Matrix Access Control (optional)
+#
+# Lists of space-separated entries. Example:
+# matrix_bot_chatgpt_matrix_whitelist: ":{{ matrix_domain }} :second-domain.com :third-domain.com"
 matrix_bot_chatgpt_matrix_blacklist: ''
 matrix_bot_chatgpt_matrix_whitelist: ':{{ matrix_domain }}'