Improve the semantic of seq-some

Update seq-some to return non-nil if the predicate returns non-nil for
any element of the seq, in which case the returned value is the one
returned by the predicate.

* lisp/emacs-lisp/seq.el (seq-some): Update the function and its
  docstring.
* test/automated/seq-tests.el (test-seq-some): Add a regression test.
* doc/lispref/sequences.texi (Sequence Functions): Update the
  documentation for seq-some.

1 files changed, 8 insertions, 3 deletions

diff --git a/doc/lispref/sequences.texi b/doc/lispref/sequences.texi
index 22ae9959602..f73779bd9ce 100644
--- a/doc/lispref/sequences.texi
+++ b/doc/lispref/sequences.texi
@@ -558,18 +558,23 @@ calling @var{function}.
 @end defun
 
 @defun seq-some predicate sequence
-  This function returns the first member of sequence for which @var{predicate}
-returns non-@code{nil}.
+  This function returns non-@code{nil} if @var{predicate} returns
+non-@code{nil} for any element of @var{sequence}.  If so, the returned
+value is the value returned by @var{predicate}.
 
 @example
 @group
 (seq-some #'numberp ["abc" 1 nil])
-@result{} 1
+@result{} t
 @end group
 @group
 (seq-some #'numberp ["abc" "def"])
 @result{} nil
 @end group
+@group
+(seq-some #'null ["abc" 1 nil])
+@result{} t
+@end group
 @end example
 @end defun