Show command aliases in help with setting to disable (#3040)

* Update help.py

* Create 3040.enhance.rst

* remove towncrier entry

* Make it i18n friendly.

* That was uneeded to change this actually.

* ...

* ..

* .

* Add a setting for aliases.

* DOTS

* Update redbot/core/core_commands.py

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

* Address requested changes maybe

* New format + changes requested.

* okay we'll get there someday

* honk

* aaaaaaaaaaaaaaa

* Black

* Fix missing humanize_timedelta import.

* style

* Two things from my very old pending review, see commit desc

```py
            valid_alias_list = [
                af
                for a in aliases
                if (af := f"{a}")
                and len(af) < 500
                and ((a_counter + len(af)) < 500)
                and (a_counter := a_counter + len(af))
            ]
```
^ This can be simplified:
```suggestion
            valid_alias_list = [
                alias
                for alias in aliases
                if (a_counter := a_counter + len(alias)) < 500
            ]
```
Although I think it would be somewhat clearer to use a `for` loop rather than a list comprehension (+ we can just `break` when there's not gonna be another alias that could fit in the list since it's sorted):
```suggestion
            valid_alias_list = []

            for alias in aliases:
                if (a_counter := a_counter + len(alias)) < 500:
                    valid_alias_list.append(alias)
                else:
                    break
```

* style *again*

* use qualified name of the parent command

* meh

* another meh

* Revert the last commit...

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>
Co-authored-by: Drapersniper <27962761+drapersniper@users.noreply.github.com>

redbot/core/bot.py

@@ -110,6 +110,7 @@ class RedBase(
             help__delete_delay=0,
             help__use_menus=False,
             help__show_hidden=False,
+            help__show_aliases=True,
             help__verify_checks=True,
             help__verify_exists=False,
             help__tagline="",