Update compatibility.md...

The note that there is a small difference in the use of `sprint`, `sprintf`, `ToString` to output in hexadecimal format as to the Fable version outputting a negative size and the magnitude as compared to DotNet just outputting the binary format seems to no longer be true with Fable version 4.13, as shown by the following code
```fable
let test0 = sprintf "%X" -10
let test1 = sprintf "%X" -10L
printfn "%s, %s" test0 test1
```
which outputs the following
```
FFFFFFF6, FFFFFFFFFFFFFFF6
```
without a negative sign to be seen...

Author: GordonBGood

docs/docs/javascript/compatibility.md

@@ -229,7 +229,3 @@ The resulting printed list of pseudo-random numbers does not work in Fable:
 
 * When accurate low-order bit arithmetic is needed and overflow can result in numbers larger than 2^53 use `int64`, `uint64`, which use exact 64 bits, instead of `int32`, `uint32`.
 * Alternately, truncate all arithmetic with `>>> 0` or `>>> 0u` as appropriate before numbers can get larger than 2^53: `let rng (s:int32) = 10001*s + 12345 >>> 0`
-
-### Printing
-
-One small change from .NET in `printf`, `sprintf`, `ToString`. Negative signed integers are printed in hexadecimal format as sign + magnitude, in .NET they are printed as two's complement bit patterns.