Use multiline text for crate conflict diagnostics

[estebank]

After:

error[E0464]: multiple matching crates for `libc`
--> /checkout/src/rustc/dlmalloc_shim/../../dlmalloc/src/linux.rs:1:1
|
1 | extern crate libc;
| ^^^^^^^^^^^^^^^^^^
|
= note: candidates:
crate `libc`: /checkout/obj/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-658d35794c10b003.rlib
crate `libc`: /checkout/obj/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-f32a17a3111b01aa.rlib

Before:

error[E0464]: multiple matching crates for `libc`
--> /checkout/src/rustc/dlmalloc_shim/../../dlmalloc/src/linux.rs:1:1
|
1 | extern crate libc;
| ^^^^^^^^^^^^^^^^^^
|
= note: candidates:
= note: path: /checkout/obj/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-658d35794c10b003.rlib
= note: crate name: libc
= note: path: /checkout/obj/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-f32a17a3111b01aa.rlib
= note: crate name: libc

[estebank]

r? @arielb1

[kennytm]

What is the motivation? The new one doesn't look clearer than the old one.

[estebank]

@kennytm I felt some of the text was redundant as all you care about is the path (I feel that even the crate name could be removed), but even if we keep exactly the same wording I'd prefer if these were all one note with multiple lines, instead of being multiple disconnected notes for the sake of third party tools that can then display the text consistently, instead as independent disjointed notes.

[shepmaster]

Ping from triage, @arielb1 — will you be able to take a look at this sometime soon?

[arielb1]

@bors r+

[bors]

📌 Commit 7e2cd70 has been approved by arielb1

[bors]

⌛ Testing commit 7e2cd702c23a906d762c564faf7ab78b45c0b2ec with merge 47b8216478537dde3e2dfe09ad94c2384595d1d9...

[bors]

💔 Test failed - status-travis

[arielb1]

test failure:

[00:57:26] failures:
[00:57:26] [run-make] run-make/many-crates-but-no-match

[estebank]

@bors r=arielb1

[bors]

📌 Commit 5eb5e91 has been approved by arielb1

[bors]

⌛ Testing commit 5eb5e91 with merge eb44c89...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: arielb1
Pushing eb44c89 to master...