Updated diagnostic message.

install.sh

@@ -456,7 +456,8 @@ if (( DOCTOR_READY == 0 ))
 then
 	printf '%s\n' \
 		"Launcher files were installed, but this host is not ready to run the game." \
-		"Resolve the diagnostics above, then run the launcher command again." >&2
+		"The exact cause is listed under 'Blocking diagnostics' above; optional tools do not block launch." \
+		"Re-run the check with: ${BIN_HOME}/pristontale-eu doctor" >&2
 	exit 1
 fi