Edits not saved

[Otto-AA]

Using the edit function for a .txt file allows changing the text, but it couldn't be saved that way.

[Otto-AA]

Fixed step by step in:

• https://github.com/Otto-AA/solid-filemanager/commit/44bcd2d5002e830a60d0e0c7eab1517a77b2183e
• https://github.com/Otto-AA/solid-filemanager/commit/66b5d01e5c2e2677d26be5189a32e889ac140290
• https://github.com/Otto-AA/solid-filemanager/commit/f767efb5a0ab7ee52fccb9750cf6713d5395afdf
• https://github.com/Otto-AA/solid-filemanager/commit/648a1bb20f0d91bb438672fd06c6d93fb18a637d