Merge from origin/emacs-26

a5da653 * src/editfns.c (Fnarrow_to_region): Doc fix.  (Bug#35163)
646d33d Fix doc strings of 'vc-version-diff' and 'vc-version-ediff'
a30a6c3 Improve documentation of set-window-start
92ce2dd Improve documentation of window parameters
6dc42c5 Improve commentary in frame.el
a8cffcf Fix typo in a doc string
9e79f19 (emacs-26) ; * src/fontset.c (set-fontset-font): Use uppercas...

# Conflicts:
#	lisp/vc/vc.el

3 files changed, 10 insertions, 4 deletions

diff --git a/src/editfns.c b/src/editfns.c
index bfffadc733d..6fb43af4e9c 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -2686,8 +2686,9 @@ but is not deleted; if you save the buffer in a file, the invisible
 text is included in the file.  \\[widen] makes all visible again.
 See also `save-restriction'.
 
-When calling from a program, pass two arguments; positions (integers
-or markers) bounding the text that should remain visible.  */)
+When calling from Lisp, pass two arguments START and END:
+positions (integers or markers) bounding the text that should
+remain visible.  */)
   (register Lisp_Object start, Lisp_Object end)
 {
   CHECK_FIXNUM_COERCE_MARKER (start);
diff --git a/src/fontset.c b/src/fontset.c
index 2729fae6ee9..eec1e0da4cc 100644
--- a/src/fontset.c
+++ b/src/fontset.c
@@ -1444,7 +1444,7 @@ or t for the default fontset.
 
 TARGET may be a single character to use FONT-SPEC for.
 
-Target may be a cons (FROM . TO), where FROM and TO are characters.
+TARGET may be a cons (FROM . TO), where FROM and TO are characters.
 In that case, use FONT-SPEC for all the characters in the range
 between FROM and TO (inclusive).
 
diff --git a/src/window.c b/src/window.c
index f911c0c7d44..ef2ed638508 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1796,7 +1796,12 @@ DEFUN ("set-window-start", Fset_window_start, Sset_window_start, 2, 3, 0,
        doc: /* Make display in WINDOW start at position POS in WINDOW's buffer.
 WINDOW must be a live window and defaults to the selected one.  Return
 POS.  Optional third arg NOFORCE non-nil inhibits next redisplay from
-overriding motion of point in order to display at this exact start.  */)
+overriding motion of point in order to display at this exact start.
+
+For reliable setting of WINDOW start position, make sure point is
+at a position that will be visible when that start is in effect,
+otherwise there's a chance POS will be disregarded, e.g., if point
+winds up in a partially-visible line.  */)
   (Lisp_Object window, Lisp_Object pos, Lisp_Object noforce)
 {
   register struct window *w = decode_live_window (window);