Allow key symbols in keybinding labels

[eugenesvk]

Currently all keys in config are using letters for both modifiers and actual keys
This hurts readability when you have to deal with remapping in big batches

For example

'A-A'	= 'cmd' # the letters look the same
'h'  	= 'cmd' #
'H'  	= 'cmd' # H is ⇧h though for some reason ⇧ is not on the side with all other modifiers
'A-,'	= 'cmd' # 
'A-<'	= 'cmd' # < is ⇧, but it's not immediately visible
'C-h'	= 'cmd'
'C-x'	= 'cmd'

The better alternative would be to allow and option to replace modifier letters with modifier symbols
(you can also ditch the unnecessary quotes as there is already a separator between keys and values, and allow literal =)
↓ now it's obvious which modifier is used since the same modifier is in the same column

⇧ ⎇ a 	: cmd # the letters look the same... NOT, there is only one letter!
     h	: cmd #
⇧   h 	: cmd # the difference with h is much more apparent
   ⎇, 	: cmd # 
⇧ ⎇,  	: cmd # it's obvious that this is the same physical ,comma, key like in↑
 ⎈  h 	: cmd
 ⎈  x 	: cmd

• And in the future when you'd add differentiation between left and right modifiers, you could easily do this

‹⇧  ‹⎇ a	: cmd
       h	: cmd
⇧›     h	: cmd
     ⎇, 	: cmd
⇧   ⎇,  	: cmd
  ‹⎈  h 	: cmd
  ⎈›  x 	: cmd

• The same principle allows to use 1-symbol short (and easier to read) non-modifier keys

Key name	Representation	Symbol
Backspace	"backspace"	␈ or ⌫
Space	"space"	␠ or ␣
Return/Enter	"ret"	⏎ or ↩ or ⌤ or ␤
-	"minus"	−
Left	"left"	◀ or ←
Right	"right"	▶ or →
Up	"up"	▲ or ↑
Down	"down"	▼ or ↓
Home	"home"	⇤ or ⤒ or ↖
End	"end"	⇥ or ⤓ or ↘
Page Up	"pageup"	⇞
Page Down	"pagedown"	⇟
Tab	"tab"	⭾
Delete	"del"	␡ or ⌦
Insert	"ins"	⎀
Escape	"esc"	⎋

• ... an the command palette could display shorter and easier to visually differentiate messages, so instead of
  <A-left> you'd just have
  ⎇◀