Tangent on Path node unclear output

The « Tangent on Path » node returns an angle in degrees clockwise from the +X axis. However this is really not clear. The tooltip states:
> Determines the angle of the tangent at a point on the path, given by its progression from 0 to 1 along the path.
> If multiple subpaths make up the path, the whole number part of the progression value selects the subpath and the decimal part determines the position along it.

The angle of the tangent of a bézier curve is often expressed as a unit vector [such as on Pomax's bezierinfo](https://pomax.github.io/bezierinfo/#pointvectors). It is very easy for a user to assume that this might be the case (I did). This is especially true since non connected nodes do not get type hints about the output type. It is also possible that they do not know from where the angle is measured since it is never stated. Also why clockwise? I generally see anticlockwise from +X in e.g. argument of complex number.

Tangent on Path ノードとその tooltip のテキストを見つけ、次にそのノードが角度出力をどのように公開しているかを確認します。結果が度単位の角度であること、+X 軸から時計回りに測定されることを明確にし、単位ベクトル出力とは異なることを示します。ノードの動作を変更せずに tooltip がこれらの曖昧さを解消できれば完了です。

索引モデルが issue の本文から書いたものです。