docs: updated @param tags, added missing function descriptions, other minor changes

Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

src/button/button.h

@@ -68,7 +68,7 @@ typedef struct _button_context {
 /**
  * button init function
  *
- * @param gpio Pin to use
+ * @param pin Pin to use
  */
 button_context button_init(int pin);
 

src/button/button.hpp

@@ -59,7 +59,7 @@ class Button{
         /**
          * button constructor
          *
-         * @param gpio Pin to use
+         * @param pin Pin to use
          */
         Button(unsigned int pin);
         /**