Annotation - Free Text - modified by MuPDF

[GitHubRulesOK]

When adding Free Text Annotation the characters supported by SumatraPDF/MuPDF are limited to Courier/Helvetica characters thus cause problems

The odd feature is foreign characters seem to be acceptable in other annotation such as text highlight comments

2154 comments Issue with polish comments MuPdf.pdf

Here the block on the left is text where annotation as highlight copied comment works well
The lower entry is Free Text from MuPDF but would be similar from SumatraPDF
The text on the right is Free Text from SumatraPDF BUT CORRECTED in Xchange by using Arial Font

The problems are twofold since if you move the corrected version it will drop back to Helvetica and then lose the unknown characters.

[GitHubRulesOK]

closing as duplicate of #1671
MuPDF only supports PDF Standard 14 fonts in comments.