ApiDefinitionGuidelines: Remove mention of api-definitions in this repo

Signed-off-by: Gabe Goodhart <[email protected]>

README.md

@@ -29,7 +29,7 @@ The rules for merging depend on the type of change in question and its scope of
 
 ## Formatting Guidelines
 
-Design documents should be placed in [docs/](./docs). API Specifications should be placed in [api-definitions/](./api-definitions).
+Design documents should be placed in [docs/](./docs).
 
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