Throw for two annotations in the same line

Author: pomber

packages/mdx/src/smooth-code/annotations.tsx

@@ -205,6 +205,12 @@ function annotateMultilineSide(
   while (lineIndex < lines.length) {
     const annotation = annotations[0]
     let line = lines[lineIndex]
+    if (
+      annotation &&
+      getLineNumber(line) > annotation.lineNumbers.start
+    ) {
+      throw "Code Hike can't handle two annotations for the same line"
+    }
     if (
       annotation &&
       getLineNumber(line) === annotation.lineNumbers.start