merge bitcoin#27937: i2p documentation updates

doc/i2p.md

@@ -9,16 +9,16 @@ started with I2P terminology.
 
 ## Run Dash Core with an I2P router (proxy)
 
-A running I2P router (proxy) with [SAM](https://geti2p.net/en/docs/api/samv3)
-enabled is required. Options include:
+A running I2P router (proxy) is required with the [SAM](https://geti2p.net/en/docs/api/samv3)
+application bridge enabled. The following routers are recommended for use with Dash Core:
 
 - [i2prouter (I2P Router)](https://geti2p.net), the official implementation in
-  Java
+  Java. The SAM bridge is not enabled by default; it must be started manually,
+  or configured to start automatically, in the Clients page in the
+  router console (`http://127.0.0.1:7657/configclients`) or in the `clients.config` file.
 - [i2pd (I2P Daemon)](https://github.com/PurpleI2P/i2pd)
   ([documentation](https://i2pd.readthedocs.io/en/latest)), a lighter
-  alternative in C++
-- [i2p-zero](https://github.com/i2p-zero/i2p-zero)
-- [other alternatives](https://en.wikipedia.org/wiki/I2P#Routers)
+  alternative in C++. It enables the SAM bridge by default.
 
 Note the IP address and port the SAM proxy is listening to; usually, it is
 `127.0.0.1:7656`.
@@ -123,8 +123,7 @@ to connect to the I2P network. Any I2P router that supports it can be used.
 
 ## Ports in I2P and Dash Core
 
-Dash Core uses the [SAM v3.1](https://geti2p.net/en/docs/api/samv3)
-protocol. One particularity of SAM v3.1 is that it does not support ports,
+One particularity of SAM v3.1 is that it does not support ports,
 unlike newer versions of SAM (v3.2 and up) that do support them and default the
 port numbers to 0. From the point of view of peers that use newer versions of
 SAM or other protocols that support ports, a SAM v3.1 peer is connecting to them