Plugin disables mermaid highlighting in mmd files

[vstirbu]

It seems that the plugin disables the syntax highlighting when diagrams are in separate files.

When the Preview extension is disabled, the syntax highlight works

When the Preview extension is enabled, the syntax highlight is gone

Regards!

Originally posted by @ppseprus in #54 (comment)

[GaryBer]

A fix: bpruitt-goddard/vscode-mermaid-syntax-highlight#21

[vstirbu]

thanks for the update!