Shadowing core "I" is too messy. As soon as ed is loaded in memory,
nothing else that isn't "i-aware" can be loaded anymore.

I guess that's why "contexts" exist in Starting Forth, but adding
this concept just for allowing the shadowing of core words seems
overkill to me. Renaming I to i in ed seems better.

This was becoming heavy to manage.

Written from VE!

This is the first commit I do entirely in VE. It's a habit I'm planning
on taking as it helps a lot to find usability issues.

It simplifies things. Also, removed ';' which became useless.

Kinda proud of this one. Efficiently piggy-backing on the Block
Editor, keeping things simple, and yet, building power into the
editor.

The indicator is going to be empty most of the time and will be
emitted by the mode changer directly. That's going to the upper-right
corner and the status bar avoids emitting in that area.

Also, add insert and find buffers to the header, making it 3 lines
high.

Also, fix the "I" overshadowing word which wasn't operating on the
proper RSP level.

Also, fix I which didn't mark the block as dirty.

Also, add MODE indirection.

Now that the boot binary is fully cross-compiled, there's no use for
the linker anymore. Theoretically, it could still be useful, but I
can't think of a real use case.

Let's take it out of the picture. If it's ever needed again, I'll
know where to find it.