Documentation: Add repository license choice to ort.yml documentation

Resolves #3396.

Signed-off-by: Stephanie Neubauer <Stephanie.Neubauer@bosch.io>

docs/config-file-ort-yml.md

@@ -266,7 +266,7 @@ resolutions:
 ### When to Use License Choices
 
 For multi-licensed dependencies a specific license can be selected.
-The license choice can be applied to a package.
+The license choice can be applied to a package or globally to an SPDX expression in the project.
 A choice is only valid for licenses combined with the SPDX operator `OR`.
 The choices are applied in the evaluator, and the reporter to the effective license of a package, which is calculated
 by the chosen [LicenseView](../model/src/main/kotlin/licenses/LicenseView.kt).
@@ -300,6 +300,22 @@ license_choices:
     # The result would be: C AND E
 ```
 
+### License Choice for the Project
+
+To globally select a license from an SPDX expression, that offers a choice, an SPDX expression for a `given` and a
+`choice` must be provided.
+The `choice` is applied to the whole `given` SPDX expression. 
+The license choices for a project can be overwritten by applying a 
+[license choice to a package](#license-choice-by-package).
+
+e.g.
+```yaml
+license_choices:
+  repository_license_choice:
+  - given: "A OR B"
+    choice: "B"
+```
+
 ---
 **NOTE**