[docs][cf] Mention use from self in the self-migration doc.

Bug: 71088
Change-Id: I77ceeb26d47effaa5c4b1fdaf205ca8f78453cb9
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/559553
Commit-Queue: Gabe Schine <thatguy@google.com>
Reviewed-by: Gary Bressler <geb@google.com>
diff --git a/docs/development/components/v2/migration.md b/docs/development/components/v2/migration.md
index 8f676e4..68b8dc4 100644
--- a/docs/development/components/v2/migration.md
+++ b/docs/development/components/v2/migration.md
@@ -245,6 +245,11 @@
     ffx scrutiny shell "search.components --url {{ '<var label="component">my_component.cm</var>' }}$"
     ```
 
+Note: it is valid to `use` from `self` in the unusual case that your component
+both consumes and publishes the same protocol. You'll know this is the case
+when the "services" section in your `.cmx` references a protocol that is mapped
+to the same component's URL in a `services.config` file.
+
 ## Migrate the tests {#migrate-tests}
 
 In most cases, tests for v1 components are themselves v1 components. The first