That's standard markdown

You can also force new lines by ending a line with two spaces:

End with 2 spaces of the end of the line like this
Then this appears on a new line

Otherwise with one space or no spaces at the end of a line, markdown dictates concatenating the lines

End with 1 space of the end of the line like this Then this gets concatenated on the end of a previous line.

or

End with no spaces of the end of the line like this Then this gets concatenated on the end of a previous line, but with a space mysteriously appearing between the concatenated parts.