Apply some cleanup for recent merge

Combine 1/(rows+1) with u8g.getHeight() to get rowHeight and just use
that.

Marlin/dogm_lcd_implementation.h

@@ -393,10 +393,13 @@ void lcd_implementation_drawedit(const char* pstr, char* value) {
 
   if (strlen_P(pstr) > LCD_WIDTH - 2 - strlen(value)) rows = 2;
 
-  u8g.setPrintPos(                                     0, u8g.getHeight() *  1/(1+rows) + DOG_CHAR_HEIGHT_EDIT/2); //1/(1+rows) = 1/2 or 1/3
+  const float kHalfChar = DOG_CHAR_HEIGHT_EDIT / 2;
+  float rowHeight = u8g.getHeight() / (rows + 1); // 1/(rows+1) = 1/2 or 1/3
+
+  u8g.setPrintPos(0, rowHeight + kHalfChar);
   lcd_printPGM(pstr);
   u8g.print(':');
-  u8g.setPrintPos((lcd_width-1-strlen(value))*char_width, u8g.getHeight()*rows/(1+rows) + DOG_CHAR_HEIGHT_EDIT/2); //rows/(1+rows) = 1/2 or 2/3
+  u8g.setPrintPos((lcd_width-1-strlen(value)) * char_width, rows * rowHeight + kHalfChar);
   u8g.print(value);
 }