Make it an option that highlight search (hlsearch) won't be overriden by error highlight

[david0u0]

Is your feature request related to a problem? Please describe.

As shown in the image, the highlight color of my search result my_inst (yellow) is overriden by the error highlight (red)

It would be great to let the user configure weather they want hlsearch or error to have higher priority

Describe the solution you'd like

Introduce a new variable, e.g. g:LanguageClient_HighlightPriority = ['hls', 'error'], so that user can configure the priority

Describe alternatives you've considered

Maybe the option to disable error highlight completely?

Thanks for reading :)