print module path

[japaric]

depends on knurling-rs/defmt#167

[japaric]

I think we may want to format the module path in a separate line, right align it or something because right now it makes the start column of the log message uneven:

0.000000 INFO  lpc_app::foo::baz | hello
└─ src/foo.rs:2
0.000001 INFO  lpc_app::bar::quux | world
└─ src/bar.rs:2
0.000002 INFO  hello::__cortex_m_rt_main | Hello, world!
└─ src/bin/hello.rs:10