Refactor: HTTP clients, unified HTTP2/QUIC options

docs/configuration/shared/http2.md

@@ -0,0 +1,43 @@
+---
+icon: material/new-box
+---
+
+!!! question "Since sing-box 1.14.0"
+
+### Structure
+
+```json
+{
+  "idle_timeout": "",
+  "keep_alive_period": "",
+  "stream_receive_window": "",
+  "connection_receive_window": "",
+  "max_concurrent_streams": 0
+}
+```
+
+### Fields
+
+#### idle_timeout
+
+Idle connection timeout, in golang's Duration format.
+
+#### keep_alive_period
+
+Keep alive period, in golang's Duration format.
+
+#### stream_receive_window
+
+HTTP2 stream-level flow-control receive window size.
+
+Accepts memory size format, e.g. `"64 MB"`.
+
+#### connection_receive_window
+
+HTTP2 connection-level flow-control receive window size.
+
+Accepts memory size format, e.g. `"64 MB"`.
+
+#### max_concurrent_streams
+
+Maximum concurrent streams per connection.