Fixed legacy default Markdown/Snippet notes bug

Fixed a bug where a note or snippet is created before the pull request and you ran Boostnote for the first time after the pr and you firstly created a note or markdown and only then returned to the old default notes and you couldn't highlight

browser/components/CodeEditor.js

@@ -520,10 +520,6 @@ export default class CodeEditor extends React.Component {
   handleHighlight (editor, changeObject) {
     const lines = editor.options.linesHighlighted
 
-    if (lines == null) {
-      return
-    }
-
     if (!lines.includes(changeObject)) {
       lines.push(changeObject)
       editor.addLineClass(changeObject, 'text', 'CodeMirror-activeline-background')

browser/main/Detail/MarkdownNoteDetail.js

@@ -47,11 +47,6 @@ class MarkdownNoteDetail extends React.Component {
       editorType: props.config.editor.type
     }
 
-    let lines = this.state.note.linesHighlighted
-    if (lines === undefined) {
-      lines = []
-    }
-
     this.dispatchTimer = null
 
     this.toggleLockButton = this.handleToggleLockButton.bind(this)
@@ -78,7 +73,7 @@ class MarkdownNoteDetail extends React.Component {
     if (!this.state.isMovingNote && (isNewNote || hasDeletedTags)) {
       if (this.saveQueue != null) this.saveNow()
       this.setState({
-        note: Object.assign({}, nextProps.note)
+        note: Object.assign({linesHighlighted: []}, nextProps.note)
       }, () => {
         this.refs.content.reload()
         if (this.refs.tags) this.refs.tags.reset()

browser/main/Detail/SnippetNoteDetail.js

@@ -48,16 +48,10 @@ class SnippetNoteDetail extends React.Component {
       note: Object.assign({
         description: ''
       }, props.note, {
-        snippets: props.note.snippets.map((snippet) => Object.assign({}, snippet))
+        snippets: props.note.snippets.map((snippet) => Object.assign({linesHighlighted: []}, snippet))
       })
     }
 
-    this.state.note.snippets.forEach(function (s) {
-      if (s.linesHighlighted === undefined) {
-        s.linesHighlighted = []
-      }
-    })
-
     this.scrollToNextTabThreshold = 0.7
     this.generateToc = () => this.handleGenerateToc()
   }
@@ -82,8 +76,9 @@ class SnippetNoteDetail extends React.Component {
       const nextNote = Object.assign({
         description: ''
       }, nextProps.note, {
-        snippets: nextProps.note.snippets.map((snippet) => Object.assign({}, snippet))
+        snippets: nextProps.note.snippets.map((snippet) => Object.assign({linesHighlighted: []}, snippet))
       })
+
       this.setState({
         snippetIndex: 0,
         note: nextNote
@@ -694,10 +689,8 @@ class SnippetNoteDetail extends React.Component {
 
     const viewList = note.snippets.map((snippet, index) => {
       const isActive = this.state.snippetIndex === index
-
       let syntax = CodeMirror.findModeByName(convertModeName(snippet.mode))
       if (syntax == null) syntax = CodeMirror.findModeByName('Plain Text')
-
       return <div styleName='tabView'
         key={index}
         style={{zIndex: isActive ? 5 : 4}}