Add missing apostrophe for possessive form

Author: benjamin-dcs

custom_components/file_plusplus/translations/en.json

@@ -19,7 +19,7 @@
         },
         "data_description": {
           "file_path": "The local file path to retrieve the sensor value from",
-          "value_template": "A template to render the sensors value based on the file content",
+          "value_template": "A template to render the sensor's value based on the file content",
           "unit_of_measurement": "Unit of measurement for the sensor"
         }
       },
@@ -67,4 +67,4 @@
       "message": "Write access to {filename} failed: {exc}."
     }
   }
-}
+}