feat: SQLite3::ForkSafety.suppress_warnings!

For frameworks like Rails where it's expected to sometimes fork with
open writable connections.

lib/sqlite3/fork_safety.rb

@@ -17,6 +17,7 @@ def _fork
 
     @databases = []
     @mutex = Mutex.new
+    @suppress = false
 
     class << self
       def hook!
@@ -30,7 +31,7 @@ def track(database)
       end
 
       def discard
-        warned = false
+        warned = @suppress
         @databases.each do |db|
           next unless db.weakref_alive?
 
@@ -49,6 +50,11 @@ def discard
         end
         @databases.clear
       end
+
+      # Call to suppress the fork-related warnings.
+      def suppress_warnings!
+        @suppress = true
+      end
     end
   end
 end