Merge bitcoin/bitcoin#21709: doc: update reduce-memory.md and bitcoin.conf -maxconnections info

300234a doc: update bitcoin.conf maxconnections info (Jon Atack)
9268270 doc: update reduce-memory.md peer connections info (Jon Atack)

Pull request description:

  This patch updates the documentation in `doc/reduce-memory.md` and `share/examples/bitcoin.conf` regarding the peer connections limits and `-maxconnections`

ACKs for top commit:
  jarolrod:
    re-ACK 300234a
  laanwj:
    ACK 300234a
  prayank23:
    ACK bitcoin/bitcoin@300234a

Tree-SHA512: 90f53626124afb50706e6a3b644bc7bb800bb7cf41ae7062c20c17b3d9bdf4a8d73b4cf188faec9113d772596f7e4bc36a4a69481cacb92cc55d5956181d0c31

Author: laanwj

doc/reduce-memory.md

@@ -24,9 +24,13 @@ The size of some in-memory caches can be reduced. As caches trade off memory usa
 
 ## Number of peers
 
-- `-maxconnections=<n>` - the maximum number of connections, this defaults to 125. Each active connection takes up some
-  memory. This option applies only if incoming connections are enabled, otherwise the number of connections will never
-  be more than 10. Of the 10 outbound peers, there can be 8 full-relay connections and 2 block-relay-only ones.
+- `-maxconnections=<n>` - the maximum number of connections, which defaults to 125. Each active connection takes up some
+  memory. This option applies only if inbound connections are enabled; otherwise, the number of connections will not
+  be more than 11. Of the 11 outbound peers, there can be 8 full-relay connections, 2 block-relay-only ones,
+  and occasionally 1 short-lived feeler or extra outbound block-relay-only connection.
+
+- These limits do not apply to connections added manually with the `-addnode` configuration option or
+  the `addnode` RPC, which have a separate limit of 8 connections.
 
 ## Thread configuration
 

share/examples/bitcoin.conf

@@ -63,7 +63,12 @@
 # Port on which to listen for connections (default: 8333, testnet: 18333, signet: 38333, regtest: 18444)
 #port=
 
-# Maximum number of inbound+outbound connections.
+# Maximum number of inbound + outbound connections (default: 125). This option
+# applies only if inbound connections are enabled; otherwise, the number of connections
+# will not be more than 11: 8 full-relay connections, 2 block-relay-only ones, and
+# occasionally 1 short-lived feeler or extra outbound block-relay-only connection.
+# These limits do not apply to connections added manually with the -addnode
+# configuration option or the addnode RPC, which have a separate limit of 8 connections.
 #maxconnections=
 
 #