fix: Add null-forgiving operator in Reswap call

Updated the Reswap method call within the HtmxResponse class to turn off warnings about using a possible null string as a parameter to a method that accepts string

Author: tanczosm

src/Htmxor/Http/HtmxResponse.cs

@@ -161,7 +161,7 @@ public HtmxResponse Reswap(SwapStyle swapStyle, string? modifier = null)
 
         if (swapStyle is SwapStyle.Default)
         {
-            Reswap(modifier);
+            Reswap(modifier!);
             return this;
         }