consolidates references to LLVM and Swift into the project operations repository (#1126)

* consolidates references to LLVM and Swift into the project operations repository

* fix error in nav

Author: heckj

_data/navigation.yml

@@ -61,8 +61,6 @@
           name: contributing-code
         - title: Adding External Library Dependencies
           name: adding-external-library-dependencies
-        - title: LLVM and Swift
-          name: llvm-and-swift
     - section: Steering Groups
     - title: Ecosystem
       url: /ecosystem-steering-group/

contributing/index.md

@@ -24,3 +24,9 @@ as described in [Source Code](/documentation/source-code).
 {% include_relative _swift-evolution-process.md %}
 {% include_relative _good-first-issues.md %}
 {% include_relative _contributing-code.md %}
+
+### LLVM and Swift
+
+For more information about the clone of the LLVM repository, see
+[LLVM and Swift](https://github.com/swiftlang/project-operations/blob/main/llvm-and-swift.md)
+in the [project-operations](https://github.com/swiftlang/project-operations/) repository.

documentation/source-code/index.md

@@ -73,7 +73,10 @@ file](https://github.com/swiftlang/swift/blob/main/README.md).
 Swift builds upon several other open-source projects, most notably
 [the LLVM Compiler Infrastructure](http://llvm.org). Swift's clones of
 the repositories of those open-source projects contain Swift-specific
-changes and are merged regularly from their upstream sources. For more information about the clone of LLVM repository, see the section on [LLVM and Swift](/contributing/#llvm-and-swift).
+changes and are merged regularly from their upstream sources. 
+For more information about the clone of the LLVM repository, see
+[LLVM and Swift](https://github.com/swiftlang/project-operations/blob/main/llvm-and-swift.md)
+in the [project-operations](https://github.com/swiftlang/project-operations/) repository.
 
 [llvm-project](https://github.com/swiftlang/llvm-project)
 : The source code for [LLVM](http://llvm.org), with a handful of Swift-specific additions. Merged regularly from the [LLVM sources at llvm.org](https://github.com/llvm/llvm-project).