Basics docs TYPE MISMATCH: sqrt >> isEven >> not

[geofflangenderfer]

This shows up in a comment and in the docs.

A compilable example would save beginners' time. For example:

> composed = cos >> sin
<function> : Float -> Float
> composed pi
-0.8414709848078965 : Float
> sin (cos pi)
-0.8414709848078965 : Float
> sin (cos pi) == composed pi
True : Bool

I believe it's an error:

>import Arithmetic
> sqrt
<function> : Float -> Float
> Arithmetic.isEven
<function> : Int -> Bool
> not
<function> : Bool -> Bool
> sqrt >> Arithmetic.isEven >> not
-- TYPE MISMATCH ---------------------------------------------------------- REPL

The right argument of (>>) is causing problems.

4|   sqrt >> Arithmetic.isEven >> not
             ^^^^^^^^^^^^^^^^^^^^^^^^
The right argument is:

    Int -> Bool

But (>>) needs the right argument to be:

    Float -> c

Hint: With operators like (>>) I always check the left side first. If it seems
fine, I assume it is correct and check the right side. So the problem may be in
how the left and right arguments interact!

Note: Read <https://elm-lang.org/0.19.1/implicit-casts> to learn why Elm does
not implicitly convert Ints to Floats. Use toFloat and round to do explicit
conversions.

Here's a correction:

> checkSqrtOdd x = sqrt x - (x |> sqrt |> floor |> toFloat) > 0.001
> checkSqrtOdd 15
True : Bool
> checkSqrtOdd 16
False : Bool
> checkSqrtOdd 17
True : Bool

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