bring back 'write number'

docs/reference/serial/write-value.md

@@ -32,5 +32,5 @@ basic.forever(() => {
 
 ### See also
 
-[serial](/device/serial), [write value](/reference/serial/write-value)
+[serial](/device/serial), [write line](/reference/serial/write-line)
 

libs/microbit/serial.ts

@@ -14,17 +14,24 @@ namespace serial {
         writeString("\r\n");
     }
 
+    /**
+     * Prints a numeric value to the serial
+     */
+    export function writeNumber(value: number): void {
+        writeString(value.toString());
+    }
+
     /**
      * Writes a ``name: value`` pair line to the serial.
      * @param name name of the value stream, eg: x
      * @param value to write
      */
-    //% help=/reference/serial/write-value
     //% weight=80
     //% blockId=serial_writevalue block="serial|write %name|= %value"
     export function writeValue(name: string, value: number): void {
         writeString(name);
-        writeString(":");
-        writeLine(value.toString());
+        writeString(": ");
+        writeNumber(value);
+        writeLine("");
     }
 }