Enable -out:<filename> for doc subcommand

[InKryption]

The logic for writing the .odin-doc file to the value assigned to out_filepath already exists, this just enables it on the CLI frontend.

[Kelimion]

The way I read this code, it would take the path given in -out as a base and still append .odin-doc to it? So perhaps the help text should reflect that -out:foo would create a documentation file called foo.odin-doc.

[InKryption]

To be clear, it always outputs a file named. Ie -out:<filename> produces <filename>.odin-doc, and -out:<filename>.odin-doc produces the same.

[Kelimion]

Yes. My point is that -out allows you to specify the base name. The extension - if present - will be stripped and replaced, so it would be useful for the help text to reflect that it allows you to set the base name, in case it leads them to believe that -out:foo.bar would generate a doc file called foo.bar.

[InKryption]

Will address when I get off my flight