docs: api doc for i18n (#29289)

PR Close #29289

packages/core/src/di/injector_compatibility.ts

@@ -70,18 +70,24 @@ export function injectInjectorOnly<T>(
 
 /**
  * Injects a token from the currently active injector.
+ * Must be used in the context of a factory function such as one defined for an
+ * `InjectionToken`. Throws an error if not called from such a context.
  *
- * This function must be used in the context of a factory function such as one defined for an
- * `InjectionToken`, and will throw an error if not called from such a context.
+ * Within such a factory function, using this function to request injection of a dependency
+ * is faster and more type-safe than providing an additional array of dependencies
+ * (as has been common with `useFactory` providers).
+ *
+ * @param token The injection token for the dependency to be injected.
+ * @param flags Optional flags that control how injection is executed.
+ * The flags correspond to injection strategies that can be specified with
+ * parameter decorators `@Host`, `@Self`, `@SkipSef`, and `@Optional`.
+ * @returns True if injection is successful, null otherwise.
  *
  * @usageNotes
+ *
  * ### Example
  *
- * {@example core/di/ts/injector_spec.ts region='ShakeableInjectionToken'}
- *
- * Within such a factory function `inject` is utilized to request injection of a dependency, instead
- * of providing an additional array of dependencies as was common to do with `useFactory` providers.
- * `inject` is faster and more type-safe.
+ * {@example core/di/ts/injector_spec.ts region='ShakableInjectionToken'}
  *
  * @publicApi
  */