Nick Fitzgerald 21063fd42f webidl: Make logging a little more consistently formatted
This commit makes these changes:

* Unsupported constructs always log "unsupported" for easy `grep`ing
* There is always a "<generic message> : <details>" format now, so we can easily
  use `cut` to grab the generic message and count which kinds of things are our
  biggest missing features.
* Make sure that we have different `warn!` logs for each kind of unsupported
  thing, instead of grouping them together.

Put all that together and this is the current state of `wasm-bindgen-webidl` and
`web-sys`:

```
$ grep WARN stderr.txt | grep wasm_bindgen_webidl | grep -i unsupported | cut -d ' ' -f5- | cut -d ':' -f 1 | sort | uniq -c | sort -rn
    387 Unsupported WebIDL Dictionary definition
    139 Unsupported argument type
     70 Unsupported return type
     47 Unsupported WebIDL Callback definition
     22 Unsupported WebIDL extended attribute
     18 Unsupported unnamed operation
      9 Unsupported WebIDL CallbackInterface definition
      7 Unsupported WebIDL Stringifier interface member
      7 Unsupported WebIDL Maplike interface member
      2 Unsupported webidl stringifier
      2 Unsupported WebIDL Setlike interface member
      2 Unsupported stringifier on type
```
2018-08-15 14:24:09 -07:00
..
2018-08-13 14:27:10 -07:00