Update 'radio' docs for v1 (#937)

docs/reference/radio/on-received-string.md

@@ -0,0 +1,42 @@
+# on Received String
+
+Run part of a program when the @boardname@ receives a [string](/types/string) over ``radio``.
+
+```sig
+radio.onReceivedString(function (receivedString) {})
+```
+
+## Parameters
+
+* **receivedString**: The [string](/types/string) that was sent in this packet or the empty string if this packet did not contain a string. See [send string](/reference/radio/send-string) and [send value](/reference/radio/send-value)
+
+## Example
+
+This program continuously sends a cheerful message. It also receives a messages from nearby @boardname@s. It shows these messages on the screen.
+
+```blocks
+basic.forever(() => {
+    radio.sendString("I'm happy");
+})
+radio.onReceivedString(function (receivedString) {
+    basic.showString(receivedString)
+})
+```
+
+## Troubleshooting
+
+The ``||radio:on received string||`` event can only be created once, due to the hardware restrictions.
+
+The radio set group might need to be set, synchronized , before the radio events will function.
+
+## See also
+
+[on received number](/reference/radio/on-received-number),
+[send number](/reference/radio/send-number),
+[send string](/reference/radio/send-string),
+[send value](/reference/radio/send-value),
+[set group](/reference/radio/set-group)
+
+```package
+radio
+```