Context2D: don't use an arrow to illustrate scaling in the docs.
Context2D: don't use an arrow to illustrate scaling in the docs.

The example image scales an arrow, but uses an arrow to indicate that
the next image (an arrow) is a result of the first arrow being scaled.
Instead, use a circle.

Change-Id: I8de18d4c2f3cb309681f63c31b0c9f7255d1868c
Reviewed-by: Topi Reiniö <92400b03a70fe3119347f89b476f73d34ae93598@digia.com>
Reviewed-by: Venugopal Shivashankar <5756f69ec86de98024d1d912258c6908b6f2ee8f@digia.com>

matthewvogt/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative