Improve doc strings of 'forward/backward-word-strictly'

* lisp/simple.el (backward-word): Refer to 'backward-word-strictly'
in the doc string.  Suggested by Glenn Morris <rgm@gnu.org>.
* lisp/subr.el (forward-word-strictly, backward-word-strictly):
Mention 'subword-mode' in the doc strings.

* src/syntax.c (Fforward_word): Refer to 'forward-word-strictly'
in the doc string.  (Bug#22560)

1 files changed, 9 insertions, 3 deletions

diff --git a/src/syntax.c b/src/syntax.c
index 8b5cc1df407..7e988547675 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -1536,9 +1536,15 @@ DEFUN ("forward-word", Fforward_word, Sforward_word, 0, 1, "^p",
        doc: /* Move point forward ARG words (backward if ARG is negative).
 If ARG is omitted or nil, move point forward one word.
 Normally returns t.
-If an edge of the buffer or a field boundary is reached, point is left there
-and the function returns nil.  Field boundaries are not noticed if
-`inhibit-field-text-motion' is non-nil.  */)
+If an edge of the buffer or a field boundary is reached, point is
+left there and the function returns nil.  Field boundaries are not
+noticed if `inhibit-field-text-motion' is non-nil.
+
+The word boundaries are normally determined by the buffer's syntax
+table, but `find-word-boundary-function-table', such as set up
+by `subword-mode', can change that.  If a Lisp program needs to
+move by words determined strictly by the syntax table, it should
+use `forward-word-strictly' instead.  */)
   (Lisp_Object arg)
 {
   Lisp_Object tmp;