(syms_of_buffer): enable-multibyte-characters is a user var.

src/buffer.c

@@ -3921,7 +3921,7 @@ in the current display table (if there is one).");
 
   DEFVAR_PER_BUFFER ("enable-multibyte-characters",
 		     &current_buffer->enable_multibyte_characters, Qnil,
-    "Non-nil means the buffer contents are regarded as multi-byte form\n\
+    "*Non-nil means the buffer contents are regarded as multi-byte form\n\
 of characters, not a binary code.  This affects the display, file I/O,\n\
 and behaviors of various editing commands.");