Character auto-removal for same char types doesn't work correctly

[Waqar144]

Characters such as:

* ` _ " '

don't get auto removed correctly sometimes on pressing backspace.

To fix this we need to determine whether the character being removed is an 'opening' or 'closing' character.

• Fix single quotes removal
• Fix double quotes removal
• Fix asterisk removal
• Fix backtick removal
• Fix underscore removal

Note: Looking backward for these characters is temporarily removed until proper solution is implemented.

Note: Commonmark rules for some characters might not completely apply because we are removing only one character at a time. Consider **bold**, we need to handle this in a way that removal of first asterisk results in the removal of third asterisk.

[Waqar144]

This is fixed with af48921 so I think its okay to close this for now

[pbek]

Fine with me. 😁