Document that the 'syntax-propertize-function' may move point.

The functions generated by 'syntax-propertize-rules' don't use
'save-excursion', but 'syntax-propertize' does, so we might as well
document that the 'syntax-propertize-function' may move point.

* doc/lispref/syntax.texi (Syntax Properties): Document that the
'syntax-propertize-function' may move point.

1 files changed, 8 insertions, 6 deletions

diff --git a/doc/lispref/syntax.texi b/doc/lispref/syntax.texi
index 2df6c15c4ca..bde7075b0df 100644
--- a/doc/lispref/syntax.texi
+++ b/doc/lispref/syntax.texi
@@ -572,12 +572,14 @@ The function is called by @code{syntax-ppss} (@pxref{Position Parse}),
 and by Font Lock mode during syntactic fontification (@pxref{Syntactic
 Font Lock}).  It is called with two arguments, @var{start} and
 @var{end}, which are the starting and ending positions of the text on
-which it should act.  It is allowed to call @code{syntax-ppss} on any
-position before @var{end}, but if a Lisp program calls
-@code{syntax-ppss} on some position and later modifies the buffer at
-some earlier position, then it is that program's responsibility to
-call @code{syntax-ppss-flush-cache} to flush the now obsolete info
-from the cache.
+which it should act.  It is allowed to arbitrarily move point within
+the region delimited by @var{start} and @var{end}; such motions don't
+need to use @code{save-excursion} (@pxref{Excursions}).  It is also
+allowed to call @code{syntax-ppss} on any position before @var{end},
+but if a Lisp program calls @code{syntax-ppss} on some position and
+later modifies the buffer at some earlier position, then it is that
+program's responsibility to call @code{syntax-ppss-flush-cache} to
+flush the now obsolete info from the cache.
 
 @strong{Caution:} When this variable is non-@code{nil}, Emacs removes
 @code{syntax-table} text properties arbitrarily and relies on