todo: adhere to the HTTP span naming semconv processing checklist

[flc1125]

Based on #6365 (comment), organize the following list of items that need to be processed:

• go.opentelemetry.io/contrib/instrumentation/github.com/gorilla/mux/otelmux
• go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin
• go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp

If there are any omissions, please let me know.

Reference solution:

https://github.com/open-telemetry/opentelemetry-go-contrib/pull/6365/files

References:

• https://github.com/open-telemetry/opentelemetry-specification/blob/v1.20.0/specification/trace/semantic_conventions/http.md#name

[flc1125]

To avoid repetition, synchronize as follows:

I am processing this: go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin