Update view-mode docstring

Not all the kill commands save the text in the kill ring
by default (e.g. `kill-rectangle').
It is more precise to just say that the kill commands save
the text and do not change the buffer (Bug#36741).
* lisp/view.el (view-mode): Update docstring.
1 job for emacs-26 in 25 minutes and 38 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #2722
test

00:25:38

 
Name Stage Failure
failed
test Test
Makefile:285: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
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make[1]: *** [check] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
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Makefile:951: recipe for target 'check' failed
ERROR: Job failed: exit code 1