Fix naming for function pointers with strings

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

src/Generator/Passes/DelegatesPass.cs

@@ -276,7 +276,9 @@ namespace CppSharp.Passes
             // TODO: all of this needs proper general fixing by only leaving type names
             return types.Replace("global::System.", string.Empty)
                 .Replace("[MarshalAs(UnmanagedType.LPUTF8Str)] ", string.Empty)
-                .Replace("[MarshalAs(UnmanagedType.LPWStr)] ", string.Empty)
+                .Replace("[MarshalAs(UnmanagedType.LPWStr)] string", "wstring")
+                .Replace("[MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(CppSharp.Runtime.UTF8Marshaller))] string", "string8")
+                .Replace("[MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(CppSharp.Runtime.UTF32Marshaller))] string", "string32")
                 .Replace("global::", string.Empty).Replace("*", "Ptr")
                 .Replace('.', '_').Replace(' ', '_').Replace("::", "_")
                 .Replace("[]", "Array");

src/Generator/Types/Std/Stdlib.CSharp.cs

@@ -103,7 +103,7 @@ namespace CppSharp.Types.Std
                 // This is not really right. ASCII is 7-bit only - the 8th bit is stripped; ANSI has
                 // multi-byte support via a code page. MarshalAs(UnmanagedType.LPStr) marshals as ANSI.
                 // Perhaps we need a CppSharp.Runtime.ASCIIMarshaller?
-                return new CustomType("[MarshalAs(UnmanagedType.LPStr)] string");   
+                return new CustomType("[MarshalAs(UnmanagedType.LPStr)] string");
             else if (encoding == Encoding.UTF8)
                 return new CustomType("[MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(CppSharp.Runtime.UTF8Marshaller))] string");
             else if (encoding == Encoding.Unicode || encoding == Encoding.BigEndianUnicode)

tests/CSharp/CSharp.cpp

@@ -1489,6 +1489,7 @@ void TestChar32String::UpdateString(const char32_t* s)
 }
 
 const char32_t* TestChar32String::RetrieveString() { return thirtyTwoBitConst; }
+void TestChar32String::functionPointerUTF32(void(*ptr)(const char32_t*)) {}
 
 TestChar16String::TestChar16String() : 
     sixteenBitConst(u"ქართული ენა") 

tests/CSharp/CSharp.h

@@ -1165,6 +1165,7 @@ public:
 
     void UpdateString(const char32_t* s);
     const char32_t* RetrieveString();
+    void functionPointerUTF32(void(*ptr)(const char32_t*));
 };
 
 class DLL_API TestChar16String