Remove stray ` from STM32F1 HAL

As noted in #8585

Marlin/src/HAL/HAL_STM32F1/persistent_store_impl.cpp

 bool read_data(int &pos, uint8_t* value, uint16_t size, uint16_t *crc, const bool writing/*=true*/) {
   for (int i = 0; i < size; i++) {
     uint8_t c = HAL_STM32F1_eeprom_content[pos + i];
-    if (writing) value[i] = c`;
+    if (writing) value[i] = c;
     crc16(crc, &c, 1);
   }
   pos += size;