Added KaTeX Rendering

src/lib/Codespan.svelte

@@ -0,0 +1,20 @@
+<script lang="ts">
+  export let raw
+  import katex from 'katex'
+  import 'katex/contrib/mhchem'
+
+  let renderedMath: string | undefined
+  if (raw.startsWith('`rendermath')) {
+    renderedMath = katex.renderToString(raw.replace(/`rendermath|`/g, ''), {
+      throwOnError: false,
+      displayMode: false
+    })
+  }
+
+</script>
+
+{#if renderedMath}
+  {@html renderedMath}
+{:else}
+  <code>{raw.replace(/`/g, '')}</code>
+{/if}