bug#62750: 29.0.50; Commands 'package-update' and 'package-update-all' should be called '*-upgrade'

[Dmitry Gutov]

On 10/04/2023 17:31, Stefan Monnier via Bug reports for GNU Emacs, the 
Swiss army knife of text editors wrote:
> > I don't think that "update" and "upgrade" have that clear of a semantic
> > difference in practice to necessitate a renaming.
> I'd tend to agree.

Here's an argument in favor of renaming:

These commands use the term 'update'. But package-menu-mark-upgrades, 
which has been in package.el for years, uses the term 'upgrade' in its 
name and its docstring ("all upgradable packages", etc). There are a few 
auxiliary functions which also use that term, but this is the 
public-facing one.

So now we have divergent terminology. Which implies that there is some 
difference between "upgrading" and "updating" in package.el, while there 
is none.