Fix surround cursor position calculation (#1183)

Fixes #1077. This was caused by the assumption that a block
cursor is represented as zero width internally and simply
rendered to be a single width selection, where as in reality
a block cursor is an actual single width selection in form and
function.

Behavioural changes:

1. Surround selection no longer works when cursor is _on_ a
    surround character that has matching pairs (like `'`
    or `"`). This was the intended behaviour from the start
    but worked till now because of the cursor position
    calculation mismatch.

0 files changed, 0 insertions, 0 deletions