Add translation keys for hard-coded string in ManifestListItem

locales/en/translation.json

@@ -26,6 +26,7 @@
     "listAllOpenWindows": "List all open windows",
     "manifestError": "The resource cannot be added:",
     "menu": "Menu",
+    "numItems": "{{number}} items",
     "off": "Off",
     "openInfoCompanionWindow": "Open information companion window",
     "openCanvasNavigationCompanionWindow": "Open canvas navigation companion window",

src/components/ManifestListItem.js

@@ -116,7 +116,7 @@ class ManifestListItem extends React.Component {
             </Grid>
             <Grid item xs={8} sm={4}>
               <Typography className={ns('manifest-list-item-provider')}>{provider || t('addedFromUrl')}</Typography>
-              <Typography>{`${size} items`}</Typography>
+              <Typography>{t('numItems', { number: size })}</Typography>
             </Grid>
 
             <Grid item xs={4} sm={2}>