new resolve-git-conflict operator

[t9md]

Introduce new operator command vim-mode-plus:resolve-git-conflict It replace conflicting section with ours or theirs text, which to pick is determined by at which section cursor is placed.

In following text(NOTE: 0:, 1: part represent row number, is NOT actual text)

0:
1: <<<<<<< HEAD
2: ours
3: =======
4: theirs
5: >>>>>>> their-branch
6:

When executed, it replace whole conflicting section(row 1 to row 5) with ours or theirs.

• Executed at row 0: do nothing
• Executed at row 1: replace with ours
• Executed at row 2: replace with ours
• Executed at row 3: do nothing
• Executed at row 4: replace with theirs
• Executed at row 5: replace with theirs
• Executed at row 6: do nothing