fix: use string overload of Contains for netstandard2.0 compatibility

Replace char literal '.' with string literal "." in String.Contains calls
at lines 1664 and 8161, as the char overload is not available in netstandard2.0.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

src/ProvidedTypes.fs

@@ -1661,11 +1661,11 @@ and ProvidedTypeDefinition(isTgt: bool, container:TypeContainer, className: stri
         let sc = if ignoreCase then StringComparison.OrdinalIgnoreCase else StringComparison.Ordinal
         this.GetInterfaces()
         |> Array.tryFind (fun t ->
-            if name.Contains('.') then String.Equals(t.FullName, name, sc)
+            if name.Contains(".") then String.Equals(t.FullName, name, sc)
             else String.Equals(t.Name, name, sc))
         |> Option.toObj
 
-    override __.GetInterfaces() = getInterfaces()  
+    override __.GetInterfaces() = getInterfaces()
 
 
     override __.MakeArrayType() = ProvidedTypeSymbol(ProvidedTypeSymbolKind.SDArray, [this], typeBuilder) :> Type
@@ -8158,7 +8158,7 @@ namespace ProviderImplementation.ProvidedTypes
             let sc = if ignoreCase then StringComparison.OrdinalIgnoreCase else StringComparison.Ordinal
             this.GetInterfaces()
             |> Array.tryFind (fun t ->
-                if name.Contains('.') then String.Equals(t.FullName, name, sc)
+                if name.Contains(".") then String.Equals(t.FullName, name, sc)
                 else String.Equals(t.Name, name, sc))
             |> Option.toObj
         override this.GetElementType() = notRequired this "GetElementType" inp.Name