wasm zig source rendering: fix annotation location off-by-one

Author: andrewrk

lib/docs/wasm/html_render.zig

@@ -91,7 +91,7 @@ pub fn fileSourceHtml(
         while (true) {
             if (next_annotate_index >= options.source_location_annotations.len) break;
             const next_annotation = options.source_location_annotations[next_annotate_index];
-            if (cursor < next_annotation.file_byte_offset) break;
+            if (cursor <= next_annotation.file_byte_offset) break;
             try out.writer(gpa).print("<span id=\"{s}{d}\"></span>", .{
                 options.annotation_prefix, next_annotation.dom_id,
             });