Fixed last nonfunctional changes made earlier

Now iterates in the SnippetNoteDetail constructor the snippets and if linesHighlighted is not defined assigns an empty array

browser/main/lib/dataApi/createSnippet.js

@@ -10,7 +10,7 @@ function createSnippet (snippetFile) {
       name: 'Unnamed snippet',
       prefix: [],
       content: '',
-      linesHighlighted: [],
+      linesHighlighted: []
     }
     fetchSnippet(null, snippetFile).then((snippets) => {
       snippets.push(newSnippet)

browser/main/lib/dataApi/migrateFromV5Storage.js

@@ -88,7 +88,7 @@ function importAll (storage, data) {
               name: article.mode,
               mode: article.mode,
               content: article.content,
-              linesHighlighted: article.linesHighlighted,
+              linesHighlighted: article.linesHighlighted
             }]
           }
           notes.push(newNote)

browser/main/lib/dataApi/updateNote.js

@@ -118,8 +118,6 @@ function updateNote (storageKey, noteKey, input) {
 
       if (noteData.type === 'SNIPPET_NOTE') {
         noteData.title
-        if(noteData.linesHighlighted = null)
-          noteData.linesHighlighted = [];
       }
 
       Object.assign(noteData, input, {