Fixed newline issue

[AjobK]

closes #333

What is it supposed to do
When you press Shift+Enter it shouldn't send your comment. Only when you exclusively press enter.

How can we test your branch

• Type a comment
• Press shift+enter (Should make new line)
• Type more stuff
• Do all kinds of random key combinations if you want
• Press enter
• Post should be sent with newlines and all

Additional notes
Things to keep in mind regarding the PR that don't fit in the previous two headings.

1. General checklist

• [x] a. Tested happy flow.
• [x] b. Tested unhappy flow.
• [x] c. No unexpected exceptions.
• [x] d. No code with high complexity. (Big O)
• [x] e. EOF newline.
• [x] f. No linter warnings or errors.

2. If relevant, front-end checklist

• [x] a. Responsive. (Desktop all the way to mobile 320px)
• [x] b. Using SCSS variables where relevant.
• [x] c. Relevant class names
• [x] d. No modified global SCSS properties, except if necessary and fully tested the impact.
• [x] e. Checked caniuse for more modern CSS properties.

3. If relevant, back-end checklist

• [ ] a. No unhandled promise rejections.
• [ ] b. Seeders still functional.
• [ ] c. No primary-key violations.
• [ ] d. Normalization, at least 3NF.
• [ ] e. Used guards (middleware) where necessary and tested if route is guarded.

4. If relevant, test these browsers

• [x] a. Chrome
• [x] b. Firefox
• [x] c. Opera
• [x] d. Edge
• [ ] e. Safari

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PR Rules
1. Add relevant labels.
2. Select at least two reviewers.
3. Assign all reviewers allowed to merge the branch, including yourself.
4. If relevant to the sprint, put related issue in 'Awaiting Approval' column on project board.
5. Add to the corresponding milestone.

Reviewer info
1. You can use aliases to refer to specific PR checklist items. For example 'Hey @JohnDoe, for this line please check 3.a and 1.d.'
2. Where possible, please use the suggestions feature in github so the author has a better idea of the solution you had in mind.

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