Character escaping in Qute doesn't work

[wgresshoff]

Describe the bug
Characters like '&' aren't escaped.
qute-test.zip

Expected behavior
Characters like '&', '"', ... should be escaped to '&', '"' etc.

Actual behavior
The html output contains invalid characters like '&' ...

To Reproduce

Link to a small reproducer (preferably a Maven project if the issue is not Gradle-specific).

Or attach an archive containing the reproducer to the issue.

Steps to reproduce the behavior:
1.
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Configuration

# Add your application.properties here, if applicable.

Screenshots
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Environment (please complete the following information):

• Output of uname -a or ver: Linux 5.8.16-300.fc33.x86_64 Switch to the Maven distributed copy of the SubstrateVM annotations #1 SMP Mon Oct 19 13:18:33 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
• Output of java -version: openjdk 11.0.9 2020-10-20
  OpenJDK Runtime Environment 18.9 (build 11.0.9+11)
  OpenJDK 64-Bit Server VM 18.9 (build 11.0.9+11, mixed mode, sharing)
• GraalVM version (if different from Java): ---
• Quarkus version or git rev: 1.9.1.Final
• Build tool (ie. output of mvnw --version or gradlew --version): Maven 3.6.3

Additional context
(Add any other context about the problem here.)

[quarkusbot]

/cc @mkouba