disable documentation comment warnings in DcCore (in deltachat.h, they're not compatible to what we're using in rust/c)

DcCore/DcCore.xcodeproj/project.pbxproj

@@ -296,7 +296,7 @@
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
-				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = NO;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
@@ -360,7 +360,7 @@
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
-				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = NO;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;