make filling chars (and, thus, erase line/char) unset wrap (#2831)

EraseInLine calls `FillConsoleOutputCharacterW()`. In filling the row with
chars, we were setting the wrap flag. We need to specifically not do this on
ANY _FILL_ operation. Now a fill operation UNSETS the wrap flag if we fill to
the end of the line.

Originally, we had a boolean `setWrap` that would mean...
- **true**: if writing to the end of the row, SET the wrap value to true
- **false**: if writing to the end of the row, DON'T CHANGE the wrap value

Now we're making this bool a std::optional to allow for a ternary state. This
allows for us to handle the following cases completely. Refer to the table
below:

,- current wrap value
|     ,- are we filling the last cell in the row?
|     |     ,- new wrap value
|     |     |     ,- comments
|--   |--   |--   |
| 0   | 0   | 0   |
| 0   | 1   | 0   |
| 0   | 1   | 1   | THIS CASE WAS HANDLED CORRECTLY
| 1   | 0   | 0   | THIS CASE WAS UNHANDLED
| 1   | 0   | 1   |
| 1   | 1   | 1   |

To handle that special case (1-0-0), we need to UNSET the wrap. So now, we have
~setWrap~ `wrap` mean the following:
- **true**: if writing to the end of the row, SET the wrap value to TRUE
- **false**: if writing to the end of the row, SET the wrap value to FALSE
- **nullopt**: leave the wrap value as it is

Closes #1126

src/buffer/out/textBuffer.cpp

@@ -318,10 +318,12 @@ OutputCellIterator TextBuffer::Write(const OutputCellIterator givenIt)
 // Arguments:
 // - givenIt - Iterator representing output cell data to write
 // - target - the row/column to start writing the text to
+// - wrap - change the wrap flag if we hit the end of the row while writing and there's still more data
 // Return Value:
 // - The final position of the iterator
 OutputCellIterator TextBuffer::Write(const OutputCellIterator givenIt,
-                                     const COORD target)
+                                     const COORD target,
+                                     const std::optional<bool> wrap)
 {
     // Make mutable copy so we can walk.
     auto it = givenIt;
@@ -336,7 +338,8 @@ OutputCellIterator TextBuffer::Write(const OutputCellIterator givenIt,
     while (it && size.IsInBounds(lineTarget))
     {
         // Attempt to write as much data as possible onto this line.
-        it = WriteLine(it, lineTarget, true);
+        // NOTE: if wrap = true/false, we want to set the line's wrap to true/false (respectively) if we reach the end of the line
+        it = WriteLine(it, lineTarget, wrap);
 
         // Move to the next line down.
         lineTarget.X = 0;
@@ -351,13 +354,13 @@ OutputCellIterator TextBuffer::Write(const OutputCellIterator givenIt,
 // Arguments:
 // - givenIt - The iterator that will dereference into cell data to insert
 // - target - Coordinate targeted within output buffer
-// - setWrap - Whether we should try to set the wrap flag if we write up to the end of the line and have more data
+// - wrap - change the wrap flag if we hit the end of the row while writing and there's still more data in the iterator.
 // - limitRight - Optionally restrict the right boundary for writing (e.g. stop writing earlier than the end of line)
 // Return Value:
 // - The iterator, but advanced to where we stopped writing. Use to find input consumed length or cells written length.
 OutputCellIterator TextBuffer::WriteLine(const OutputCellIterator givenIt,
                                          const COORD target,
-                                         const bool setWrap,
+                                         const std::optional<bool> wrap,
                                          std::optional<size_t> limitRight)
 {
     // If we're not in bounds, exit early.
@@ -368,7 +371,7 @@ OutputCellIterator TextBuffer::WriteLine(const OutputCellIterator givenIt,
 
     //  Get the row and write the cells
     ROW& row = GetRowByOffset(target.Y);
-    const auto newIt = row.WriteCells(givenIt, target.X, setWrap, limitRight);
+    const auto newIt = row.WriteCells(givenIt, target.X, wrap, limitRight);
 
     // Take the cell distance written and notify that it needs to be repainted.
     const auto written = newIt.GetCellDistance(givenIt);