Added smart parentheses and double quotes

[melvingelbard]

• Added smart parentheses '(' and ')'.

1. Typing an opening parenthesis '(' will automatically add a closing one ')' and move the caret in the middle of both: (_ is the caret position, not a character here)

Before:

_

After:

(_)

2. Typing a closing parenthesis when the next character is already a closing parenthesis will simply move the caret forward one position:

Before:

(_)

After:

()_

And also, Before:

doSomething(true_)

After (the closing parenthesis is not repeated):

doSomething(true)_

• Smart double quotes '"'.

1. Typing double quotes '"' will automatically add another following one and move the caret in-between:

Before:

_

After:

"_"

2. Typing double quotes '"' when the next character is already a double quotes will simply move the caret forward one position:

Before:

"_"

After:

""_

And also, Before:

"Hello World_"

After:

"Hello World"_

Note

This PR cannot be merged until these notes are checked manually:

• The smart parentheses behaviour is currently triggered by either typing the left/right parenthesis keys or Shift + 9/0, which might not be applicable to all keyboards/locales.
• The smart double quotes behaviour is currently triggered by either typing the double quotes key or Shift + 2, which might not be applicable to all keyboards/locales.