Add a trailing newline to OpenAPI spec output

[jgallagher]

Fixes a papercut - if one opens an OpenAPI spec JSON file in an editor that wants to save files with trailing newlines, that breaks later expectorate tests. This changes the output to include a trailing newline instead.

[ahl]

I don't know if this makes me dumb or a genius, but my editor strips out the trailing newline in json documents. I'm sure I could configure it to preserve them... but it does seem that this may be an annoyance in either direction.

[jclulow]

In general I believe most tools expect a UNIX text file to be either totally empty (0 bytes) or a whole number of lines, each terminated by a linefeed. What text editor is removing them?!

[ahl]

Vim

[sunshowers]

I think the general expectation is as @jclulow said, to always have a trailing newline yeah. Hence e.g. git shows the "No newline at end of file" message.

[ahl]

I see: "an industry standard best practice"!

[jgallagher]

I got something I'm interpreting as permission-to-merge from Adam offline.

[ahl]

I got something I'm interpreting as permission-to-merge from Adam offline.

I think my exact words were "over my dead body"