New Serial topic

docs/reference/serial/read-line.md

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+# Serial Read Line
+
+Read a line of text from the serial port.
+
+```sig
+serial.readLine();
+```
+
+#### ~hint
+
+This function expects the line it reads to be terminated with the `\r`
+character.  If your terminal software does not terminate lines with
+`\r`, this function will probably never return a value.
+
+#### ~
+
+### Returns
+
+* a [string](/reference/types/string) containing input from the serial port, such as a response typed by a user
+
+### Example
+
+The following example requests the user's name, then repeats it to greet the user.
+
+```blocks
+basic.forever(() => {
+    serial.writeLine("What is your name?");
+    let answer = serial.readLine();
+    serial.writeString("Hello,");
+    serial.writeLine(answer);
+});
+```
+
+### See also
+
+[serial](/device/serial),
+[serial write line](/reference/serial/write-line),
+[serial write value](/reference/serial/write-value)