Merge from origin/emacs-27

7722b510aa (origin/emacs-27) Another improvement in documentation of ...
8d5c70d73a Improve documentation of profiler
0ffef0b46b Document 'ispell-program-name'
7be610f911 Fix documentation of 'face-extend-p'

# Conflicts:
#	doc/lispref/debugging.texi

diff --cc doc/emacs/fixit.texi
Simple merge

diff --cc doc/lispref/debugging.texi
index de98d2206e24d1be046cf5e4277b5fe5b6366f1f,ed3160f45484fdcab769743052f4a434ee0ad4d9..e458d76d5d0cb322dcc0cd206a6a50e72a403ac4
--- 1/doc/lispref/debugging.texi
--- 2/doc/lispref/debugging.texi
+++ b/doc/lispref/debugging.texi
@@@ -1009,14 -1010,13 +1010,14 @@@ profiling, so we don't recommend leavin
  actually running the code you want to examine).
  
  The profiler report buffer shows, on each line, a function that was
- called, preceded by how much resources (cpu or memory) it used in
 -called, followed by how much CPU resources it used in
++called, preceded by how much CPU resources it used in
  absolute and percentage terms since profiling started.  If a given
 -line has a @samp{+} symbol at the left-hand side, you can expand that
 -line by typing @kbd{@key{RET}}, in order to see the function(s) called
 -by the higher-level function.  Use a prefix argument (@kbd{C-u
 -@key{RET}}) to see the whole call tree below a function.  Pressing
 -@kbd{@key{RET}} again will collapse back to the original state.
 +line has a @samp{+} symbol to the left of the function name, you can
 +expand that line by typing @kbd{@key{RET}}, in order to see the
 +function(s) called by the higher-level function.  Use a prefix
 +argument (@kbd{C-u @key{RET}}) to see the whole call tree below a
 +function.  Pressing @kbd{@key{RET}} again will collapse back to the
 +original state.
  
  Press @kbd{j} or @kbd{mouse-2} to jump to the definition of a function
  at point.  Press @kbd{d} to view a function's documentation.  You can

diff --cc doc/lispref/display.texi
Simple merge

diff --cc lisp/profiler.el
index 64d71f4aab298edaf4160b3a9c73e057b03ecf6d,7cdd3511277288903e5312ffac310a11cc7b7e5d..8145e51d75d0c4d08f44a225fb6ac982018c0bfc
--- 1/lisp/profiler.el
--- 2/lisp/profiler.el
+++ b/lisp/profiler.el
@@@ -822,11 -812,15 +822,15 @@@ below entry at point.
  (defun profiler-start (mode)
    "Start/restart profilers.
  MODE can be one of `cpu', `mem', or `cpu+mem'.
- If MODE is `cpu' or `cpu+mem', time-based profiler will be started.
- Also, if MODE is `mem' or `cpu+mem', then memory profiler will be started."
+ If MODE is `cpu' or `cpu+mem', start the time-based profiler,
+    whereby CPU is sampled periodically using the SIGPROF signal.
+ If MODE is `mem' or `cpu+mem', start profiler that samples CPU
+    whenever memory-allocation functions are called -- this is useful
+    if SIGPROF is not supported, or is unreliable, or is not sampling
+    at a high enough frequency."
    (interactive
     (list (if (not (fboundp 'profiler-cpu-start)) 'mem
 -           (intern (completing-read "Mode (default cpu): "
 +           (intern (completing-read (format-prompt "Mode" "cpu")
                                      '("cpu" "mem" "cpu+mem")
                                      nil t nil nil "cpu")))))
    (cl-ecase mode