[1.21] Selecting commands, output with the context menu is totally in the wrong place

[zadjii-msft]

open pwsh, with shell integration enabled

do a

cd Z:\dev\public\OpenConsole\
git status
dir
foo
whatever

try and right-click select the output of dir, and it's... wrong:

surely, I'm the murderer, but I could have swore there were tests for this

[zadjii-msft]

https://github.com/microsoft/terminal/blame/f36d589a8eb60fe9ff4c8efaad8eac088647e8a8/src/cascadia/TerminalCore/terminalrenderdata.cpp#L205-L214

or prior:

https://github.com/microsoft/terminal/blame/d632c39cc3cef3075f09d881e03801518310d641/src/cascadia/TerminalCore/terminalrenderdata.cpp#L171-L207

Just staring at that in isolation, it's not clear to me what coordinate system the coord params of

SelectNewRegion(const til::point coordStart, const til::point coordEnd)

are

[zadjii-msft]

diff --git a/src/cascadia/TerminalCore/terminalrenderdata.cpp b/src/cascadia/TerminalCore/terminalrenderdata.cpp
index ec28b59d5..3d989f31f 100644
--- a/src/cascadia/TerminalCore/terminalrenderdata.cpp
+++ b/src/cascadia/TerminalCore/terminalrenderdata.cpp
@@ -199,7 +199,7 @@ til::CoordType Terminal::_ScrollToPoints(const til::point coordStart, const til:
         _NotifyScrollEvent();
     }

-    return _scrollOffset;
+    return _VisibleStartIndex();
 }

 void Terminal::SelectNewRegion(const til::point coordStart, const til::point coordEnd)

this fixes it. Need to write a test