use "fs" instead of "spiffs" as spiffs is implementation specific

interface/src/system/SystemStatusForm.tsx

@@ -7,7 +7,7 @@ import DevicesIcon from '@material-ui/icons/Devices';
 import MemoryIcon from '@material-ui/icons/Memory';
 import ShowChartIcon from '@material-ui/icons/ShowChart';
 import SdStorageIcon from '@material-ui/icons/SdStorage';
-import StorageIcon from '@material-ui/icons/Storage';
+import FolderIcon from '@material-ui/icons/Folder';
 import DataUsageIcon from '@material-ui/icons/DataUsage';
 import PowerSettingsNewIcon from '@material-ui/icons/PowerSettingsNew';
 import RefreshIcon from '@material-ui/icons/Refresh';
@@ -97,10 +97,10 @@ class SystemStatusForm extends Component<SystemStatusFormProps, SystemStatusForm
         <ListItem >
           <ListItemAvatar>
             <Avatar>
-              <StorageIcon />
+              <FolderIcon />
             </Avatar>
           </ListItemAvatar>
-          <ListItemText primary="SPIFFS (Used / Total)" secondary={formatNumber(data.spiffs_used) + ' / ' + formatNumber(data.spiffs_total) + ' bytes (' + formatNumber(data.spiffs_total - data.spiffs_used) + ' bytes free)'} />
+          <ListItemText primary="File System (Used / Total)" secondary={formatNumber(data.fs_used) + ' / ' + formatNumber(data.fs_total) + ' bytes (' + formatNumber(data.fs_total - data.fs_used) + ' bytes free)'} />
         </ListItem>
         <Divider variant="inset" component="li" />
       </Fragment>

interface/src/system/types.ts

@@ -8,8 +8,8 @@ export interface SystemStatus {
   sdk_version: string;
   flash_chip_size: number;
   flash_chip_speed: number;
-  spiffs_used: number;
-  spiffs_total: number;
+  fs_used: number;
+  fs_total: number;
 }
 
 export interface OTASettings {

lib/framework/SystemStatus.cpp

@@ -26,13 +26,13 @@ void SystemStatus::systemStatus(AsyncWebServerRequest* request) {
   root["flash_chip_speed"] = ESP.getFlashChipSpeed();
 
 #ifdef ESP32
-  root["spiffs_total"] = SPIFFS.totalBytes();
-  root["spiffs_used"] = SPIFFS.usedBytes();
+  root["fs_total"] = SPIFFS.totalBytes();
+  root["fs_used"] = SPIFFS.usedBytes();
 #elif defined(ESP8266)
   FSInfo fs_info;
   SPIFFS.info(fs_info);
-  root["spiffs_total"] = fs_info.totalBytes;
-  root["spiffs_used"] = fs_info.usedBytes;
+  root["fs_total"] = fs_info.totalBytes;
+  root["fs_used"] = fs_info.usedBytes;
 #endif
 
   response->setLength();