Improve documentation of string truncation APIs

* doc/lispref/display.texi (Size of Displayed Text):
* lisp/international/mule-util.el (truncate-string-to-width):
Document caveats of using 'truncate-string-to-width' when
character composition is involved.

* lisp/emacs-lisp/subr-x.el (string-limit):
* doc/lispref/strings.texi (Creating Strings): Improve the
documentation of 'string-limit'.

1 files changed, 6 insertions, 6 deletions

diff --git a/lisp/emacs-lisp/subr-x.el b/lisp/emacs-lisp/subr-x.el
index 3de666682fa..788cd0f34bf 100644
--- a/lisp/emacs-lisp/subr-x.el
+++ b/lisp/emacs-lisp/subr-x.el
@@ -264,13 +264,13 @@ result will have lines that are longer than LENGTH."
     (buffer-string)))
 
 (defun string-limit (string length &optional end coding-system)
-  "Return (up to) a LENGTH substring of STRING.
-If STRING is shorter than or equal to LENGTH, the entire string
-is returned unchanged.
+  "Return a substring of STRING that is (up to) LENGTH characters long.
+If STRING is shorter than or equal to LENGTH characters, return the
+entire string unchanged.
 
-If STRING is longer than LENGTH, return a substring consisting of
-the first LENGTH characters of STRING.  If END is non-nil, return
-the last LENGTH characters instead.
+If STRING is longer than LENGTH characters, return a substring
+consisting of the first LENGTH characters of STRING.  If END is
+non-nil, return the last LENGTH characters instead.
 
 If CODING-SYSTEM is non-nil, STRING will be encoded before
 limiting, and LENGTH is interpreted as the number of bytes to