Apply suggestions from online code review

Co-authored-by: David Hebbeker <david@hebbeker.info>

Author: FiveTeethless

lib/3rd_party_adapters/LVGL/GuiEngine.cpp

@@ -1,3 +1,7 @@
+/**
+ * \file .
+ * Connects LVGL callbacks to display driver and input device.
+ */
 #include "GuiEngine.hpp"
 #include "Screen.hpp"
 #include <Adafruit_SSD1306.h>
@@ -28,12 +32,11 @@ static void flushSSD1306Adafruit(lv_disp_drv_t *disp_drv, const lv_area_t *area,
             color_p++;
         }
     }
-    //this->display.display();  //this has been removed from here due to performance, as multiple flushes are triggert, when mor areas on screen are refreshed
+    //this->display.display();  // this has been removed from here due to performance, as multiple flushes are triggered, when more areas on screen are refreshed
     lv_disp_flush_ready(disp_drv);
 }
 
 static IKeypad *myKeypad = nullptr;
-static lv_group_t *group = nullptr;
 
 /**
  * @brief Construct a new Gui Engine:: GuiEngine object
@@ -158,10 +161,10 @@ void GuiEngine::registerKeyPad(IKeypad *keypad)
     myKeypad = keypad;
 
     // create default group for button navigation and assign input device to it
-    group = lv_group_create();
+    static lv_group_t *const group = lv_group_create();
     lv_group_set_default(group);
 
-    // Register all buttons as individual indev, so they all have their seperate "old" state (lvgl has only one "old" state per indev)
+    // Register all buttons as individual indev, so they all have their separate "old" state (lvgl has only one "old" state per indev)
     static lv_indev_drv_t indev_drv_left;
     lv_indev_drv_init(&indev_drv_left);
     indev_drv_left.type = LV_INDEV_TYPE_KEYPAD;

lib/3rd_party_adapters/LVGL/Screen.hpp

@@ -1,3 +1,7 @@
+/**
+ * \file .
+ * Converts menu items to LVGL.
+ */
 #pragma once
 
 #include <lvgl.h>

lib/application_business_rules/user_interaction/Menu.cpp

@@ -5,7 +5,7 @@
  * @brief Construct a new Menu:: Menu object
  * 
  * @param guiEngineToUse - GuiEngine to be used for display
- * @param keypad         - Keypad to get Menu controlls from
+ * @param keypad         - Keypad to get Menu controls from
  */
 Menu::Menu(IGuiEngine &guiEngineToUse, IKeypad &keypad)
     : guiEngine(guiEngineToUse)

lib/application_business_rules/user_interaction/MenuItem.cpp

@@ -14,7 +14,6 @@ MenuItemSubmenu::MenuItemSubmenu(std::string text, const MenuItemList *subMenuLi
 /**
  * @brief returns the text of this item
  * 
- * @return std::string 
  */
 std::string MenuItemSubmenu::getText() const
 {
@@ -24,7 +23,6 @@ std::string MenuItemSubmenu::getText() const
 /**
  * @brief returns a constant pointer to the constant SubMenuList
  * 
- * @return const MenuItemList* 
  */
 const MenuItemList *MenuItemSubmenu::getSubMenuList() const
 {
@@ -45,7 +43,6 @@ MenuItemSwitch::MenuItemSwitch(std::string text, bool *ptrBool)
 /**
  * @brief returns the text of this item
  * 
- * @return std::string 
  */
 std::string MenuItemSwitch::getText() const
 {
@@ -55,7 +52,6 @@ std::string MenuItemSwitch::getText() const
 /**
  * @brief returns a pointer to the modification variable
  * 
- * @return bool* 
  */
 bool *MenuItemSwitch::getPtrBool() const
 {
@@ -79,7 +75,6 @@ MenuItemValue::MenuItemValue(std::string text, double *ptrDouble, uint8_t decima
 /**
  * @brief returns the text of this item
  * 
- * @return std::string 
  */
 std::string MenuItemValue::getText() const
 {
@@ -89,7 +84,6 @@ std::string MenuItemValue::getText() const
 /**
  * @brief returns a pointer to the modification variable
  * 
- * @return double* 
  */
 double *MenuItemValue::getPtrDouble() const
 {
@@ -99,7 +93,6 @@ double *MenuItemValue::getPtrDouble() const
 /**
  * @brief returns the amount of decimal digits
  * 
- * @return uint8_t 
  */
 uint8_t MenuItemValue::getDecimals() const
 {
@@ -109,7 +102,6 @@ uint8_t MenuItemValue::getDecimals() const
 /**
  * @brief returns the minimum value
  * 
- * @return * returns 
  */
 double MenuItemValue::getMin() const
 {
@@ -119,7 +111,6 @@ double MenuItemValue::getMin() const
 /**
  * @brief returns the maximum value
  * 
- * @return * returns 
  */
 double MenuItemValue::getMax() const
 {