fix: remove explicit param from GossipSubParams constructor (#1080)

libp2p/protocols/pubsub/gossipsub.nim

@@ -51,7 +51,6 @@ when defined(libp2p_expensive_metrics):
 
 proc init*(
   _: type[GossipSubParams],
-  explicit = true,
   pruneBackoff = 1.minutes,
   unsubscribeBackoff = 5.seconds,
   floodPublish = true,

libp2p/protocols/pubsub/gossipsub/types.nim

@@ -102,6 +102,11 @@ type
     behaviourPenalty*: float64 # the eventual penalty score
 
   GossipSubParams* {.public.} = object
+    # explicit is used to check if the GossipSubParams instance was created by the user either passing params to GossipSubParams(...)
+    # or GossipSubParams.init(...). In the first case explicit should be set to true when calling the Nim constructor.
+    # In the second case, the param isn't necessary and should be always be set to true by init.
+    # If none of those options were used, it means the instance was created using Nim default values.
+    # In this case, GossipSubParams.init() should be called when initing GossipSub to set the values to their default value defined by nim-libp2p.
     explicit*: bool
     pruneBackoff*: Duration
     unsubscribeBackoff*: Duration