Fix html typo

I'm assuming this was accidental since the intended error is a missing
input file.

1 files changed, 1 insertions, 1 deletions

diff --git a/subplot.md b/subplot.md
index d6a2cb2..238f94b 100644
--- a/subplot.md
+++ b/subplot.md
@@ -2135,7 +2135,7 @@ missing file.
 ~~~scenario
 given file missing-binding.md
 and an installed subplot
-when I try to run subplot docgen missing-binding.md -o foo.htmlh
+when I try to run subplot docgen missing-binding.md -o foo.html
 then command fails
 and stderr contains ": missing-binding.yaml:"
 ~~~