Fix placeholder text for editor

[itsthejoker]

Relevant issue: #248

Description:

Converts the initial text from actual content in the text field to the SimpleMDE-specific placeholder text.

Checklist:

• [x] Code Quality
• [ ] Pep-8
• [ ] Tests (if applicable)
• [x] Success Criteria Met
• [ ] Inline Documentation
• [ ] Wiki Documentation (if applicable)

[itsthejoker]

I don't know why the build on the static analysis is failing but it's not part of this PR