keyboard: Switch default maps for surrounding pairs to the delimiters themselves

[Pokey Rule]

in this map:

cursorless/packages/cursorless-vscode/src/keyboard/keyboard-config.fixture.json

Lines 85 to 100 in 5f94e08

 "cursorless.experimental.keyboard.modal.keybindings.pairedDelimiter": { 
   "wl": "angleBrackets", 
   "wt": "backtickQuotes", 
   "wb": "curlyBrackets", 
   "wd": "doubleQuotes", 
   "wwd": "escapedDoubleQuotes", 
   "wwp": "escapedParentheses", 
   "wws": "escapedSquareBrackets", 
   "wwq": "escapedSingleQuotes", 
   "wp": "parentheses", 
   "wq": "singleQuotes", 
   "ws": "squareBrackets", 
   "wg": "string", 
   "wj": "any", 
   "wk": "collectionBoundary" 
 } 

we would eg change wb to {