Update included_software.md

Clean up wording

Co-authored-by: rstavchansky <rachael@netlify.com>

Author: vbrown608

included_software.md

@@ -34,8 +34,8 @@ The specific patch versions included will depend on when the image was last buil
   * 1.7 (default)
 * Swift - `SWIFT_VERSION`, `.swift-version`
   * Not installed by default.
-  * Supports any version that `swiftenv` can install newer than `4.x`. Versions `4.x` and below will not work due to incompatible shared libraries.
-  * 5.2 will be installed if `Package.swift` is present and no version is specified.
+  * Supports any version that `swiftenv` can install later than `4.x`. Versions `4.x` and earlier will not work due to incompatible shared libraries.
+  * 5.2 is installed if `Package.swift` is present and no version is specified with `SWIFT_VERSION` or `.swift-version`.
 
 ### Tools