Fix typos, add button section

ImGui-Widgets.md

@@ -1,9 +1,7 @@
 # Text
 ## ImGui::Text
 
-Outputs a formatted text. The format options is like `printf`
-
-### Input
+Draws formatted text. The format options are like `printf`.
 
 ### Example
 ```c++
@@ -11,6 +9,15 @@ ImGui::Text("Hello world %f", 42);
 ```
 
 # Main
+## ImGui::Button
+Draws a button and returns whether it was clicked or not.
+### Example
+```c++
+if (ImGui::Button("Button"))
+{
+    printf("Button Clicked");
+}
+```
 
 # Combo Box