table: Fix comment

The previous one didn't make a lot of sense, now that I read it again
after some time.
table: Add fullwidth numbers

An early tester of IBus Cangjie just asked me if we could do this, and
it seems like a reasonable improvement.
table: Drop 'hvpi' code for 氐

The 氐 character has 2 Cangjie codes in our data: 'hpm' and 'hvpi'.

However, depending on the reference sources (dictionaries, CBF's
website, the chinesecj.com forum,...), we can find either only 'hpm',
or both.

That's all a bit confusing...

Doing some tests with Cangjie users, they only knew about the 'hpm'
code, never the 'hvpi' one (although once told about it, they were
usually able to understand how to decompose 氐 in 'hvpi').

That tells me that 'hpm' is absolutely necessary, but not 'hvpi'.

But the above doesn't warrant a removal, though.

Unfortunately, 'hvpi' is actually causing us trouble, as Quick users
don't expect to see 氐 as the third result when typing 'hi'. In fact,
they don't expect it at all when typing 'hi', only when typing 'hm'.

One possibility is to handle this character differently for Quick than
for Cangjie, but that would be a pretty invasive change.

The simpler possibility is to just remove the 'hvpi' code for 氐, at
least for now.

If someone really asks for 'hvpi', we can re-introduce it in the future
and start investigating the more invasive change.