:lipstick: Deprecate backspaceToBeginningOf{Word,Line}

Rename functions `backspaceToBeginningOfWord` to `deleteToBeginningOfWord` and
`backspaceToBeginningOfLine to `deleteToBeginningOfLine`.
Rename commands `editor:backspace-to-beginning-of-word` to
`delete-to-beginning-of-word` and `editor:backspace-to-beginning-of-line` to
`editor:delete-to-beginning-of-line`.

Fix #1791
merge conflict
Bug #1791 Fix typo in example group name and function names.
Merge pull request #2173 from Locke23rus/issue-1791

:lipstick: Deprecate backspaceToBeginningOf{Word,Line}