Updated ImGui Widgets (markdown)

ImGui-Widgets.md

@@ -2,7 +2,10 @@
 ## ImGui::Text
 
 Draws formatted text. The format options are like `printf`.
-
+### Function Signature
+```c++
+IMGUI_API void Text(const char* fmt, ...)
+```
 ### Example
 ```c++
 ImGui::Text("Hello world %f", 42);
@@ -11,6 +14,10 @@ ImGui::Text("Hello world %f", 42);
 # Main
 ## ImGui::Button
 Draws a button and returns whether it was clicked or not.
+### Function Signature
+```c++
+IMGUI_API bool Button(const char* label, const ImVec2& size = ImVec2(0, 0));
+```
 ### Example
 ```c++
 if (ImGui::Button("Button"))