* doc/emacs/search.texi (Query Replace): Document the meaning of
the nil value of query-replace-from-to-separator. (Bug#25482)
@var{from} is the search pattern, @var{to} is its replacement, and the
separator between them is determined by the value of the variable
@code{query-replace-from-to-separator}. Type @key{RET} to select the
-desired replacement.
+desired replacement. If the value of this variable is @code{nil},
+replacements are not added to the command history, and cannot be
+reused.
@cindex faces for highlighting query replace
@cindex query-replace face