add end for a if in the docstrings

src/i2c.jl

@@ -324,9 +324,10 @@ the error code).
 ```julia
 (b, d) = i2c_read_block_data(pi, h, 10)
 if b >= 0
-# process data
+  # process data
 else
-# process read failure
+  # process read failure
+end
 ```
 """
 function i2c_read_block_data(self::Pi, handle, reg)

src/pi.jl

@@ -758,6 +758,7 @@ then GPIO x is high.
 h = notify_open(pi)
 if h >= 0
     notify_begin(pi, h, 1234)
+end
 ```
 """
 function notify_open(self::Pi)
@@ -780,6 +781,7 @@ The following code starts notifications for GPIO 1, 4,
 h = notify_open(pi)
 if h >= 0
     notify_begin(pi, h, 1234)
+end
 ```
 """
 function notify_begin(self::Pi, handle, bits)
@@ -803,6 +805,7 @@ if h >= 0
     # ...
     notify_begin(pi, h, 1234)
     # ...
+end
 ```
 """
 function notify_pause(self::Pi, handle)
@@ -821,6 +824,7 @@ if h >= 0
     # ...
     notify_close(pi, h)
     # ...
+end
 ```
 """
 function notify_close(self::Pi, handle)
@@ -1284,14 +1288,16 @@ otherwise false.
 
 ```julia
 if wait_for_edge(pi, 23)
-print("Rising edge detected")
+  print("Rising edge detected")
 else
-print("wait for edge timed out")
+  print("wait for edge timed out")
+end
 
 if wait_for_edge(pi, 23, PiGPIO.FALLING_EDGE, 5.0)
-print("Falling edge detected")
+  print("Falling edge detected")
 else
-print("wait for falling edge timed out")
+  print("wait for falling edge timed out")
+end
 ```
 """
 function wait_for_edge(self::Pi, user_gpio, edge=RISING_EDGE, wait_timeout=60.0)

src/spiSerial.jl

@@ -121,9 +121,10 @@ the error code).
 ```julia
 (b, d) = spi_read(pi, h, 60) # read 60 bytes from device h
 if b == 60
-# process read data
+  # process read data
 else
-# error path
+  # error path
+end
 ```
 """
 function spi_read(self::Pi, handle, count)
@@ -296,7 +297,8 @@ the error code).
 ```julia
 (b, d) = serial_read(pi, h2, 100)
 if b > 0
-# process read data
+  # process read data
+end
 ```
 """
 function serial_read(self::Pi, handle, count)
@@ -349,7 +351,8 @@ device associated with handle.
 rdy = serial_data_available(pi, h1)
 
 if rdy > 0
-(b, d) = serial_read(pi, h1, rdy)
+  (b, d) = serial_read(pi, h1, rdy)
+end
 ```
 """
 function serial_data_available(self::Pi, handle)