Remove cache.writeData from local state documentation.

CHANGELOG.md

@@ -38,6 +38,9 @@
 - **[BREAKING]** Apollo Client 2.x allowed `@client` fields to be passed into the `link` chain if `resolvers` were not set in the constructor. This allowed `@client` fields to be passed into Links like `apollo-link-state`. Apollo Client 3 enforces that `@client` fields are local only, meaning they are no longer passed into the `link` chain, under any circumstances.  <br/>
   [@hwillson](https://github.com/hwillson) in [#5982](https://github.com/apollographql/apollo-client/pull/5982)
 
+- **[BREAKING]** `client|cache.writeData` have been fully removed. `writeData` usage is one of the easiest ways to turn faulty assumptions about how the cache represents data internally, into cache inconsistency and corruption. `client|cache.writeQuery`, `client|cache.writeFragment`, and/or `cache.modify` can be used to update the cache.  <br/>
+  [@benjamn](https://github.com/benjamn) in [#5923](https://github.com/apollographql/apollo-client/pull/5923)
+
 - `InMemoryCache` now supports tracing garbage collection and eviction. Note that the signature of the `evict` method has been simplified in a potentially backwards-incompatible way. <br/>
   [@benjamn](https://github.com/benjamn) in [#5310](https://github.com/apollographql/apollo-client/pull/5310)
 

docs/shared/mutation-result.mdx

@@ -12,4 +12,4 @@
 | `loading` | boolean | A boolean indicating whether your mutation is in flight |
 | `error` | ApolloError | Any errors returned from the mutation |
 | `called` | boolean | A boolean indicating if the mutate function has been called |
-| `client` | ApolloClient | Your `ApolloClient` instance. Useful for invoking cache methods outside the context of the update function, such as `client.writeData` and `client.readQuery`. |
+| `client` | ApolloClient | Your `ApolloClient` instance. Useful for invoking cache methods outside the context of the update function, such as `client.writeQuery` and `client.readQuery`. |