"Function to call to get the next buffer to search.
When this variable is set to a function that returns a buffer, then
-after typing another C-s or C-r at a failing search, the search goes
+after typing another \\[isearch-forward] or \\[isearch-backward] \
+at a failing search, the search goes
to the next buffer in the series and continues searching for the
next occurrence.
The first argument of this function is the current buffer where the
search is currently searching. It defines the base buffer relative to
which this function should find the next buffer. When the isearch
-direction is backward (when isearch-forward is nil), this function
-should return the previous buffer to search. If the second argument of
+direction is backward (when `isearch-forward' is nil), this function
+should return the previous buffer to search. If the second argument of
this function WRAP is non-nil, then it should return the first buffer
in the series; and for the backward search, it should return the last
buffer in the series.")