Update docs/ref/spec.md

Co-authored-by: Ryan Bottriell <[email protected]>

Author: dcookspi

docs/ref/spec.md

@@ -72,7 +72,7 @@ Fetches and extracts a tar archive as package source files.
 | options     | _List[[BuildOption](#buildoption)]_ | The set of inputs for the package build process                |
 | variants    | _List[[OptionMap](#optionmap)]_     | The default variants of the package options to build           |
 | validation  | _[ValidationSpec](#validationspec)_ | Modifies the default package validation process                |
-| auto_host_vars | _[HostCompat](#hostcompat)_ | The host compatibility setting for the package's builds. It covers distro, arch, os, and distro version |
+| auto_host_vars | _[HostCompat](#hostcompat)_ | The host compatibility setting for the package's builds. Depending on the value, it injects build options like distro, arch, os, and distro version |
 
 ### BuildOption