Correcting battery level UOM and adding "Edit on Github" and BLE tracker links (#3178)

Current docs list "percent" as battery level UOM when HA uses "%" to indicate percentage. Also adding the "See Also" section that has the "Edit on GitHub" link since it was missing. Included the BLE Tracker section, as well, since it seemed relevant.

components/sensor/airthings_ble.rst

@@ -154,7 +154,7 @@ the AirThings mobile app.
       - platform: copy
         source_id: bv
         name: "WaveMini Battery Level"
-        unit_of_measurement: percent
+        unit_of_measurement: "%"
         device_class: battery
         accuracy_decimals: 0
         filters:
@@ -173,10 +173,16 @@ the AirThings mobile app.
       - platform: copy
         source_id: bv
         name: "WavePlus Battery Level"
-        unit_of_measurement: percent
+        unit_of_measurement: "%"
         device_class: battery
         accuracy_decimals: 0
         filters:
           - calibrate_linear:
             - 2.2 -> 0
             - 3.1 -> 100
+
+See Also
+--------
+
+- :doc:`/components/esp32_ble_tracker`
+- :ghedit:`Edit`