Install rustc-dev component in travis and azure

Author: flip1995

.travis.yml

@@ -11,6 +11,7 @@ install:
   # Required for Racer autoconfiguration
   - rustup component add rust-src
   - rustup component add rust-analysis
+  - rustup component add rustc-dev
 matrix:
   fast_finish: true
   include:

ci/azure-test.yml

@@ -17,7 +17,7 @@ jobs:
       parameters:
         rust_version: ${{ parameters.rust }}
     - script: |
-        rustup component add rust-src rust-analysis
+        rustup component add rust-src rust-analysis rustc-dev
       displayName: Install distributed Rust source code for Racer autocompletion
     - ${{ each crate in parameters.crates }}:
       - script: cargo test -v