Rollup merge of #35573 - wdv4758h:E0138, r=jonathandturner

Rollup merge of #35573 - wdv4758h:E0138, r=jonathandturner

Update E0138 to new format

Part of #35233
Fix #35510
r? @jonathandturner

![e0138](https://cloud.githubusercontent.com/assets/2716047/17562415/7200d93c-5f5d-11e6-98ff-e15c29f40e03.png)

Question: How can I only underline the function name ? I have observed the debug output and the struct of item, but I can't find the `Span` for function name. Should I modify the struct I get to save function name's position or there is another way to get it ? (I can only find `Span`s for function attributes, inputs, outputs, blocks)