EOF is not treated like a line

[Andrew-Morozko]

Spec says:

A line is a sequence of zero or more characters other than line feed (U+000A) or carriage return (U+000D), followed by a line ending or by the end of file.

Goldmark doesn't treat the EOF as a new line, it's possible to see this in code blocks followed by the EOF:

• 4-space commonmark vs goldmark
• fenced commonmark vs goldmark

Simple workaround - append '\n' if there is no trailing newline in the input, but I wonder if it may conflict with something else.