Markdown is a way to apply unobtrusive formatting to text files to give it a bit of structure that can also be parsed so it can be presented in a GUI even more prettily than the text version.
Please remember that markdown is a text format first - you should make it readable as text. The readable GUI version comes automatically due to the nice GUI formatting, but it is easy to forget this and write markdown for GUI presentation only. Pay attention to how your text looks.
See https://stackoverflow.com/questions/729692/why-should-text-files-end-with-a-newline
A newline in a text file is a terminator, not a separator. This means each line should have a newline at the end of it, including the last line of the file.
Many editors automatically add the newline at the end of the file. Some do not. If you can configure your editor to ensure there is always a newline at the end of every line, please do so.
Because many editors do add this newline, if you commit a text file without it, when someone else edits the file, their editor will (correctly) add the newline. This causes a spurious diff in the file. Spurious