Clarify Netty instrumentation support (#11447)

Author: trask

docs/supported-libraries.md

@@ -99,7 +99,7 @@ These are the supported libraries and frameworks:
 | [Micrometer](https://micrometer.io/)                                                                                                        | 1.5+                               | [opentelemetry-micrometer-1.5](../instrumentation/micrometer/micrometer-1.5/library)                                                                                                                                                                                                                                                                                                    | none                                                                                                                                    |
 | [MongoDB Driver](https://mongodb.github.io/mongo-java-driver/)                                                                              | 3.1+                               | [opentelemetry-mongo-3.1](../instrumentation/mongo/mongo-3.1/library)                                                                                                                                                                                                                                                                                                                   | [Database Client Spans]                                                                                                                 |
 | [MyBatis](https://mybatis.org/mybatis-3/)                                                                                                   | 3.2+                               | N/A                                                                                                                                                                                                                                                                                                                                                                                     | none                                                                                                                                    |
-| [Netty](https://github.com/netty/netty)                                                                                                     | 3.8+                               | [opentelemetry-netty-4.1](../instrumentation/netty/netty-4.1/library)                                                                                                                                                                                                                                                                                                                   | [HTTP Client Spans], [HTTP Client Metrics], [HTTP Server Spans], [HTTP Server Metrics]                                                  |
+| [Netty HTTP codec [5]](https://github.com/netty/netty)                                                                                      | 3.8+                               | [opentelemetry-netty-4.1](../instrumentation/netty/netty-4.1/library)                                                                                                                                                                                                                                                                                                                   | [HTTP Client Spans], [HTTP Client Metrics], [HTTP Server Spans], [HTTP Server Metrics]                                                  |
 | [OkHttp](https://github.com/square/okhttp/)                                                                                                 | 2.2+                               | [opentelemetry-okhttp-3.0](../instrumentation/okhttp/okhttp-3.0/library)                                                                                                                                                                                                                                                                                                                | [HTTP Client Spans], [HTTP Client Metrics]                                                                                              |
 | [Oracle UCP](https://docs.oracle.com/database/121/JJUCP/)                                                                                   | 11.2+                              | [opentelemetry-oracle-ucp-11.2](../instrumentation/oracle-ucp-11.2/library)                                                                                                                                                                                                                                                                                                             | [Database Pool Metrics]                                                                                                                 |
 | [OSHI](https://github.com/oshi/oshi/)                                                                                                       | 5.3.1+                             | [opentelemetry-oshi](../instrumentation/oshi/library)                                                                                                                                                                                                                                                                                                                                   | [System Metrics] (partial support)                                                                                                      |
@@ -159,6 +159,8 @@ These are the supported libraries and frameworks:
 
 **[4]** Newer versions of the library have telemetry built-in.
 
+**[5]** Doesn't currently support capturing HTTP/2 traffic.
+
 [Elasticsearch Client Spans]: https://github.com/open-telemetry/semantic-conventions/blob/main/docs/database/elasticsearch.md
 [HTTP Server Spans]: https://github.com/open-telemetry/semantic-conventions/blob/main/docs/http/http-spans.md#http-server
 [HTTP Client Spans]: https://github.com/open-telemetry/semantic-conventions/blob/main/docs/http/http-spans.md#http-client