use original method as HTTP span name

docs/http/http-spans.md

@@ -61,13 +61,20 @@ and various HTTP versions like 1.1, 2 and SPDY.
 ## Name
 
 HTTP spans MUST follow the overall [guidelines for span names](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.22.0/specification/trace/api.md#span).
-HTTP server span names SHOULD be `{http.request.method} {http.route}` if there is a
+
+HTTP server span names SHOULD be `{method} {http.route}` if there is a
 (low-cardinality) `http.route` available.
-HTTP server span names SHOULD be `{http.request.method}` if there is no (low-cardinality)
-`http.route` available.
+
+If there is no (low-cardinality) `http.route` available, HTTP server span names
+SHOULD match `{method}`
+
 HTTP client spans have no `http.route` attribute since client-side instrumentation
-is not generally aware of the "route", and therefore HTTP client spans SHOULD use
-`{http.request.method}`.
+is not generally aware of the "route", and therefore HTTP client spans SHOULD be
+`{method}`.
+
+The `{method}` in all cases SHOULD be `{http.request.method_original}` when the original method
+is available and `{http.request.method}` otherwise.
+
 Instrumentation MUST NOT default to using URI
 path as span name, but MAY provide hooks to allow custom logic to override the
 default span name.