QGlyphRun boundingRect is offset in QQuickTextNode

The boundingRect returned by the QGlyphRuns in a QQuickTextNode when laying out a QTextDocument appear to be below the actual position of the text. For example a run at the start of the document will have the bounding rect (0,14 41x14).

This is problematic when positioning image nodes within a text node as they are positioned relative to the bounding rect of the previous node which is below the baseline if it's a text node and above it if it's an image node. Translating the text nodes up by their ascent compensates for this and ensures all node's bounding boxes are at (baseline - ascent).