PDPageContent stream warns about overwriting in overwrite mode

When updating page content stream the class PDContentStream warns about overwriting the content. Even thought the PDContentStream is explicitly set to overwrite mode.

[o.a.p.p.PDPageContentStream] - You are overwriting an existing content, you should use the append mode

This creates slight confusion when looking into logs.

The problematic code is in constructor of org/apache/pdfbox/pdmodel/PDPageContentStream.java

There should be additional check before logging the warning.