pxt-microbit Accessibility PR (#529)

* Accessibility changes

docs/reference/pins/analog-read-pin.md

@@ -7,12 +7,12 @@ Read an **analog** signal (`0` through `1023`) from the
 pins.analogReadPin(AnalogPin.P0)
 ```
 
-### Parameters
+## Parameters
 
 * ``name`` is a [string](/types/string) with the name of the pin
   you say (`P0` through `P4`, or `P10`)
 
-### Returns
+## Returns
 
 * a [number](/types/number) from `0` through `1023`
 
@@ -26,13 +26,13 @@ basic.forever(() => {
 });
 ```
 
-#### ~hint
+### ~hint
 
 If you are using **analog read pin** with another @boardname@ running **analog write pin**, then things can get tricky. Remember that the @boardname@ that runs **analog set pin** writes 0's and 1's at a very high frequency to achieve an average of the desired value. Sadly, if you try to read that average from another @boardname@, then the @boardname@ will either read 0 or 1023. You could try to read a higher number of values (e.g. a million) in a loop, then computer then average. Alternatively, you can plug in a capacitor in-between the two @boardname@s.
 
-#### ~
+### ~
 
-### See also
+## See also
 
 [@boardname@ pins](/device/pins),
 [on pin pressed](/reference/input/on-pin-pressed),