Fix bug with how the clicked-on splitter is determined, which caused us to...

Fix bug with how the clicked-on splitter is determined, which caused us to pick the wrong splitter in tmux integration mode, which caused issue 4163.

sources/PTYSplitView.m

@@ -49,7 +49,7 @@
     NSArray *subviews = [self subviews];
     NSPoint locationInWindow = [theEvent locationInWindow];
     locationInWindow.y--;
-    NSPoint locationInView = [self convertPoint:locationInWindow toView:self];
+    NSPoint locationInView = [self convertPoint:locationInWindow fromView:nil];
     int x = 0;
     int y = 0;
     int bestDistance = -1;

sources/PTYTab.m

@@ -3627,12 +3627,13 @@ static NSString* FormatRect(NSRect r) {
     }
     // Dragging looks a lot better if we turn on resizing subviews temporarily.
     for (SessionView *sv in [self sessionViews]) {
-            [sv setAutoresizesSubviews:YES];
+        [sv setAutoresizesSubviews:YES];
     }
 }
-- (void)splitView:(PTYSplitView *)splitView draggingDidEndOfSplit:(int)splitterIndex pixels:(NSSize)pxMoved
-{
+- (void)splitView:(PTYSplitView *)splitView
+  draggingDidEndOfSplit:(int)splitterIndex
+           pixels:(NSSize)pxMoved {
     if (![self isTmuxTab]) {
         // Don't care for non-tmux tabs.
         return;