Updated OllamaFunctionTool.toString to reflect what the Ollama API actually wants

Added @NotNull annotation to OllamaFunctionTool.name and OllamaFunctionTool.parameters since the documentation reports as these being required

Made sure that OllamaFunctionTool.description is actually optional as the Ollama API docs define

API/src/main/java/me/zacharias/chat/api/APITool.java

@@ -8,6 +8,8 @@ import me.zacharias.chat.ollama.OllamaFunctionTool;
 import me.zacharias.chat.ollama.OllamaPerameter;
 import me.zacharias.chat.ollama.OllamaToolRespnce;
 import me.zacharias.chat.ollama.exceptions.OllamaToolErrorException;
+import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NonNull;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.util.UriComponentsBuilder;
@@ -45,7 +47,7 @@ public class APITool extends OllamaFunctionTool {
     }
 
     @Override
-    public String name() {
+    public @NonNull String name() {
         return name;
     }
 
@@ -55,7 +57,7 @@ public class APITool extends OllamaFunctionTool {
     }
 
     @Override
-    public OllamaPerameter parameters() {
+    public @NotNull OllamaPerameter parameters() {
         OllamaPerameter.OllamaPerameterBuilder parameter = OllamaPerameter.builder();
         for (ToolArgument argument : arguments) {
             parameter.addProperty(argument.getName(), argument.getType(), argument.getDescription(), argument.isRequired());