Detect broken italics in header

[TimJentzsch]

To create italic text, the asterisk has to be placed directly after the word/sentence, without any whitespace in between. If the asterisk is placed after a space, it will render as a literal asterisk.

A formatting check should be added (probably as part of #321) which ensures that the header is using italic text correctly.

Example of erronous usage:

*Image Transcription: *

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