Fix some titles, sigs in ref docs (#2128)

* Fix some title and sigs in ref docs

* better buffer source

docs/reference/serial/read-buffer.md

@@ -26,7 +26,7 @@ The need to pause for more data is set by the @boardname@ **[serial mode](https:
 
 Read character data from the serial port one row at a time. Write the rows to an LED display connected to the I2C pins.
 
-```blocks
+```typescript
 let rowData: Buffer = null;
 for (let i = 0; i < 24; i++) {
     rowData = serial.readBuffer(80);

docs/reference/serial/write-buffer.md

@@ -16,7 +16,7 @@ You place your data characters into an existing buffer. All of the data, the len
 
 Read some characters of data from a device connected to the I2C pins. Write the data to the serial port.
 
-```blocks
+```typescript
 pins.i2cWriteNumber(132, NumberFormat.UInt8LE, 0);
 let i2cBuffer = pins.i2cReadBuffer(132, 16, false);
 serial.writeBuffer(i2cBuffer);