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Fix wrapped lines in less in Git for Windows (#5771)
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## Summary of the Pull Request

This PR resolves an issue with the Git for Windows (MSYS) version of `less`. It _doesn't_ use VT processing for emitting text tothe buffer, so when it hits `WriteCharsLegacy`, `WC_DELAY_EOL_WRAP` is NOT set.

When this happens, `less` is writing some text that's longer than the width of the buffer to the last line of the buffer. We're hitting the 
```c++
    Status = AdjustCursorPosition(screenInfo, CursorPosition, WI_IsFlagSet(dwFlags, WC_KEEP_CURSOR_VISIBLE), psScrollY);
```
call in `_stream.cpp:560`.

The cursor is _currently_ at `{40, 29}`, the _start_ of the run of text that wrapped. We're trying to adjust it to `{0, 30}`, which would be the start of the next line of the buffer. However, the buffer is only 30 lines tall, so we've got to `IncrementCircularBuffer` first, so we can move the cursor there.

When that happens, we're going to paint frame. At the end of that frame, we're going to try and paint the cursor position. The cursor is still at `{40, 29}` here, so unfortunately, the `cursorIsInDeferredWrap` check in `XtermEngine::PaintCursor` is `false`. That means, conpty is going to try to move the cursor to where the console thinks the cursor actually is at the end of this frame, which is `{40, 29}`.

If we're painting the frame because we circled the buffer, then the cursor might still be in the position it was before the text was written to the buffer to cause the buffer to circle. In that case, then we DON'T want to paint the cursor here either, because it'll cause us to manually break this line. That's okay though, the frame will be painted again, after the circling is complete.

## PR Checklist
* [x] Closes #5691
* [x] I work here
* [x] Tests added/passed
* [n/a] Requires documentation to be updated

## Detailed Description of the Pull Request / Additional comments

I suppose that's the detailed description above

## Validation Steps Performed
* ran tests
* checked that the bug was actually fixed in the Terminal
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zadjii-msft authored May 8, 2020
1 parent e3fdb1a commit 3847271
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1 change: 1 addition & 0 deletions .github/actions/spell-check/whitelist/alphabet.txt
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