sequence diagram, arrowhead instead of crosshead

[tylerlong]

sequenceDiagram
A->>B: How are you?

Generated line:

<line x1="75" y1="100" x2="275" y2="100" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#crosshead)" style="fill: none;"></line>

should be:

<line x1="75" y1="100" x2="275" y2="100" class="messageLine0" stroke-width="2" stroke="black" marker-end="url(#arrowhead)" style="fill: none;"></line>

You made a typo here:

https://github.com/knsv/mermaid/blob/b43e695da2048515e0198ca075be3cb0f1b5e564/src/diagrams/sequenceDiagram/sequenceRenderer.js#L239