Remove manual HtmlTag class

[Oliver Becker]

I would propose to remove the specialized HtmlTag class (and also HeadTag and BodyTag) and just let them be generated like other ContainerTag classes.

• the current change is not compatible to previous versions of j2html, i.e.
  ContainerTag html = html(body(h1("Hello, world!")));
  doesn't compile anymore (HtmlTag is not a ContainerTag)
• it is not possible to add attributes before the children (as you would do in HTML itself), i.e.
  html().withLang("en").with(body(h1("Hello, world!")));
  doesn't compile anymore, the attributes need to be moved to the end, resulting in
  html(body(h1("Hello, world!"))).withLang("en")
  which is for real world scenarios impractical
• the class introduces extra code that needs to be maintained (for example it needs its own render method implementation), which is IMHO somewhat error-prone (for example the first version simply forgot to render the attributes - see #138 (comment) )
• I don't see the benefit, as it would be perfectly legal to omit the body tag and create HTML like this
  html(h1("Hello, world!"))
  (see https://html.spec.whatwg.org/#syntax-tag-omission )
• finally, it is not really consistent, I mean why do we have such strict constraints for the html element, but not for other elements with a comparable strict content model, for example ul, ol, dl, or tr?

Summarized: the above disadvantages outweight the (small and questionable) advantage of enforcing a correct content model for the html element , so we should replace the manual version of this class with the corresponding generated version.

[Scott Embler]

I like the idea, and you've listed good reasons to do this. Will this cause any breaking changes for users, or is this returning it to the state it was in at v1.4.0? I'm still learning some of this history of this tag so I'd just like to know if it fits for v 1.x or v2.

[Scott Embler]

After reviewing the commit history, yes we should do this before the next release. Returning those tags to being generated fixes a lot of troubles for us.

[Scott Embler]

@obecker did you plan on creating a PR for this, or should I work on it?

[Oliver Becker]

@sembler Here you are!

Fun fact: the manual body tag missed a lot of onsomeevent attributes. Now with the generated code, this has been fixed as well.