Lift {global,local}-key-binding to Lisp

[Eli Zaretskii]

  commit a9658cd5b07e88a5d413cbb4dfd8f9d9d0c8bbf5
  Author:     Stefan Kangas <stefan@marxist.se>
  AuthorDate: Wed Jan 13 18:54:09 2021 +0100
  Commit:     Stefan Kangas <stefan@marxist.se>
  CommitDate: Wed Jan 13 18:54:09 2021 +0100

      Lift {global,local}-key-binding to Lisp

      * lisp/subr.el (local-key-binding, global-key-binding): New defuns.
      * src/keymap.c (Flocal_key_binding, Fglobal_key_binding): Remove DEFUNs.
      (syms_of_keymap): Remove defsubrs for above DEFUNs.
      * test/lisp/subr-tests.el (subr-test-local-key-binding)
      (subr-test-global-key-binding): New tests.

Stefan, why are we moving these and other functions to Lisp?  Are
there any advantages to moving them?  Is there any plan behind this
and other similar changes?

And why don't we discuss such changes before making them?

In general, unless we get some significant gains, I'd prefer not to
move around code just to move it.  If nothing else, it makes it harder
for people who, like me, are familiar with the original code, to find
stuff, because suddenly it isn't where it used to be.  The result is
that I cannot use my memory anymore, I need to consult the code each
time I need to answer some question or consider something related to
this code.  It's a needless churn, and I ask myself what do we gain in
return?