* Fix: Fix word-wrap in markdown editor

Overwrite css-property 'work-break: normal' for '.CodeMirror-wrap
pre.CodeMirror-line', which lead to words not wrapping correctly,
with 'word-break: break-word' to properly wrap words.

* Add rule for 'p.line' under .editor-markdown-preview-content

Add 'overflow-wrap: break-word;' for line in the preview of the markdown editor, so the preview properly wraps and does not overflow.