Allow to disable spell and grammar checking, or to use the right language

[adrienjoly]

This would prevent distracting red blocks everywhere when editing a comment in French language, without having to disable the browser's grammar checking (I just checked: disabling Chrome's grammar checking does not remove the red blocks):

This could be caused by a en-us language specification in any of the components being used on that page. (EDIT: I found none, from Chrome's inspector)

[adrienjoly]

Finding: The red blocks have the cm-spell-error CSS class, which seems to be added by https://github.com/sparksuite/codemirror-spell-checker

[adrienjoly]

Indeed, SimpleMDE (editor integrated into this power-up) = CodeMirror + codemirror-spell-checker, cf https://github.com/sparksuite/simplemde-markdown-editor

The spell checker could be disabled by adding the spellChecker: false prop (cf https://github.com/sparksuite/simplemde-markdown-editor#configuration) when instantiating new SimpleMDE in

comment-editor-for-trello/js/comment-editor.js

Line 111 in a71a3c9

var simplemde = new SimpleMDE({

Or it could be disabled dynamically by altering the styling of the cm-spell-error CSS class.