Error running hooks for 'WinSetOption' 'filetype=plug'

[robertmeta]

From: https://github.com/andreyorst/plug.kak/issues/73

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On OSX Catalina, with Kakoune brewed from source and suggested kakrc, plug returns an error on :plug-install or :plug-update, but loads normally when updated from the list manually.

Debug buffer:

plug.kak: Can't declare highlighters for 'kak' filetype.
          Detailed error: 2:10: 'add-highlighter' duplicate id: 'plug_keywords'
plug.kak: Can't declare highlighters for *plug* buffer.
          Detailed error: 2:6: 'add-highlighter' duplicate id: 'plug_buffer'
error running hook WinSetOption(filetype=plug)/plug-syntax: 2:6: 'add-highlighter' duplicate id: 'plug_buffer'