dependabot: bump mistletoe from 1.5.1 to 1.6.0

Bumps [mistletoe](https://github.com/miyuchina/mistletoe) from 1.5.1 to 1.6.0.
- [Release notes](https://github.com/miyuchina/mistletoe/releases)
- [Commits](miyuchina/mistletoe@v1.5.1...v1.6.0)

---
updated-dependencies:
- dependency-name: mistletoe
  dependency-version: 1.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pyproject.toml

@@ -16,7 +16,7 @@ classifiers = [
 ]
 dependencies = [
     "python-liquid2==0.4.0",
-    "mistletoe==1.5.1",
+    "mistletoe==1.6.0",
     "requests==2.34.2",
     "tiktoken==0.13.0",
     "PyYAML==6.0.3",

requirements.txt

@@ -1,5 +1,5 @@
 python-liquid2==0.4.0
-mistletoe==1.5.1
+mistletoe==1.6.0
 python-frontmatter==1.3.0
 requests==2.34.2
 rich==15.0.0