Dokka Javadoc's tag parser is case-insensitive

[qwwdfsad]

According to Javadoc specification, tags are case-sensitive, meaning that @foo and @Foo are different tags.

Currently, Dokka treats tags in a case-insensitive manner, resolving @param, @PARAM and @pArAm into the standardized @param tag. It would be nice to follow the spec here to avoid surprising behavior.

Additionally, I've verified that IDEA's Javadoc parser also treats tags in a case-sensitive manner