Updating docs with new CI triggers

Author: etcwilde

docs/ContinuousIntegration.md

@@ -159,6 +159,16 @@ Platform       | Comment | Check Status
 macOS platform | @swift-ci Please Build Toolchain macOS Platform| Swift Build Toolchain macOS Platform
 Linux platform | @swift-ci Please Build Toolchain Linux Platform| Swift Build Toolchain Linux Platform
 
+You can also build a toolchain for a specific Linux distribution
+
+Distro         | Comment                                   | Check Status
+-------------- | ----------------------------------------- | ----------------------------------------------
+UBI9           | @swift-ci build toolchain UBI9            | Swift Build Toolchain UBI9 (x86_64)
+CentOS 7       | @swift-ci build toolchain CentOS 7        | Swift Build Toolchain CentOS 7 (x86_64)
+Ubuntu 18.04   | @swift-ci build toolchain Ubuntu 18.04    | Swift Build Toolchain Ubuntu 18.04 (x86_64)
+Ubuntu 22.04   | @swift-ci build toolchain Ubuntu 22.04    | Swift Build Toolchain Ubuntu 22.04 (x86_64)
+Amazon Linux 2 | @swift-ci build toolchain Amazon Linux 2  | Swift Build Toolchain Amazon Linux 2 (x86_64)
+
 ### Build and Test Stdlib against Snapshot Toolchain
 
 To test/build the stdlib for a branch that changes only the stdlib using a last known good snapshot toolchain: