Minimal wrapper around the `mermkit` CLI.
```
cargo add mermkit
```
```rust
let result = mermkit::render("graph TD; A-->B", "svg", None, None)?;
```
```rust
let mut client = mermkit::Client::new()?;
let result = client.render("graph TD; A-->B", "svg", None, None)?;
```
-
```
export MERMKIT_BIN=/path/to/mermkit
```