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

doc/emacs/fixit.texi

@@ -263,6 +263,13 @@ systems.
 @xref{Top, Aspell,, aspell, The Aspell Manual}.
 @end ifnottex
 
+@vindex ispell-program-name
+  If you have only one of the spelling checker programs installed,
+Emacs will find it when you invoke for the first time one of the
+commands described here.  If you have more than one of them installed,
+you can control which one is used by customizing the variable
+@code{ispell-program-name}.
+
 @table @kbd
 @item M-$
 Check and correct spelling of the word at point (@code{ispell-word}).

doc/lispref/debugging.texi

@@ -997,11 +997,12 @@ start looking for ways to optimize that piece.
 @findex profiler-report
 @findex profiler-stop
 Emacs has built-in support for this.  To begin profiling, type
-@kbd{M-x profiler-start}.  You can choose to profile by processor
-usage, memory usage, or both.  Then run the code you'd like to speed
-up.  After that, type @kbd{M-x profiler-report} to display a summary
-buffer for each resource (cpu and memory) that you chose to profile.
-The names of the report buffers include the times at which the reports
+@w{@kbd{M-x profiler-start}}.  You can choose to sample CPU usage
+periodically (@code{cpu}), when memory is allocated (@code{memory}),
+or both.  Then run the code you'd like to speed up.  After that, type
+@kbd{M-x profiler-report} to display a summary buffer for CPU usage
+sampled by each type (cpu and memory) that you chose to profile.  The
+names of the report buffers include the times at which the reports
 were generated, so you can generate another report later on without
 erasing previous results.  When you have finished profiling, type
 @kbd{M-x profiler-stop} (there is a small overhead associated with
@@ -1009,7 +1010,7 @@ profiling, so we don't recommend leaving it active except when you are
 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, preceded by how much CPU resources it used in
 absolute and percentage terms since profiling started.  If a given
 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

doc/lispref/display.texi

@@ -3007,9 +3007,10 @@ This function returns non-@code{nil} if face @var{face} specifies
 a non-@code{nil} @code{:inverse-video} attribute.
 @end defun
 
-@defun face-extend-p face &optional frame
+@defun face-extend-p face &optional frame inherit
 This function returns non-@code{nil} if face @var{face} specifies
-a non-@code{nil} @code{:extend} attribute.
+a non-@code{nil} @code{:extend} attribute.  The @var{inherit} argument
+is passed to @code{face-attribute}.
 @end defun
 
 

lisp/profiler.el

@@ -822,8 +822,12 @@ 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 (format-prompt "Mode" "cpu")