Cleanup HTML functionality adding in unnecessary H2 tags

[lqiu96]

Environment details

• Programming language: Java
• OS: Linux
• Language runtime version: Java 11
• Package version: v1.6.0

Steps to reproduce

Tha YAMLUtil.cleanupHTML function is replacing the == blocks with h2 tags:
https://github.com/googleapis/java-docfx-doclet/blob/main/third_party/docfx-doclet-143274/src/main/java/com/microsoft/util/YamlUtil.java#L38

This is causing errors in the EnvironmentsClient.java file in java-orchestration-airflow:
https://github.com/googleapis/java-orchestration-airflow/blob/main/google-cloud-orchestration-airflow/src/main/java/com/google/cloud/orchestration/airflow/service/v1/EnvironmentsClient.java#L525-L542

This replaces "scikit-learn":"==0.19.0" to "scikit-learn":"<h2>0.19.0" and "botocore":"==1.7.14" to "botocore":"</h2>1.7.14"

The added h2 tags is invalid HTML and the javadoc is throwing errors.

[lqiu96]

Seems to be parsing out the Java client name header in the javadoc.
i.e.

java-docfx-doclet/third_party/docfx-doclet-143274/src/test/java/com/microsoft/samples/package-info.java

Line 19 in 24adca3

* <p>======================= SpeechClient =======================

and

java-docfx-doclet/third_party/docfx-doclet-143274/src/test/java/com/microsoft/samples/package-info.java

Line 33 in 24adca3

* <p>======================= AdaptationClient =======================

The string is generated from GAPIC: https://github.com/googleapis/gapic-generator-java/blob/f8b36168372118d6ed639263bae192647912ed43/src/main/java/com/google/api/generator/gapic/composer/ClientLibraryPackageInfoComposer.java#L81

Possible regex replacement:
=======================([^=]+)=======================
Making the regex as explicit as possible and not match anything else in the proto docs.

@eaball35 Could you let me know if the original regex is also matching something else in the javadocs?

[eaball35]

Yes, this is the correct assumption. Test it out, but your possible replacement should work. There was originally a bug filed awhile back about the way these headers appeared in ref docs like this so I just parsed it out. Ideally we could move some of this cleanup logic to the original generation in gapic generator.