Remove unexpected nested-content parameter inserted in Quick Fix

[JessicaJHee]

Fixes #841

[datho7561]

Looks pretty good, but there is a related corner case:

If you have a user tag myTag.html:

{it}

and you reference it:

{#myTag}
{/myTag}

• The old behaviour was to generate {#myTag it="it"}
• The new behaviour (with this PR) is that the code action does nothing and the warning doesn't go away when you apply the code action
• The correct behaviour is {#myTag ""}, since it refers to the first parameter without a name (see https://quarkus.io/guides/qute-reference#user_tags)

I'm wondering if you want to address this in this PR or should I file an issue so that someone will eventually get to it?

[JessicaJHee]

• The correct behaviour is {#myTag ""}, since it refers to the first parameter without a name (see https://quarkus.io/guides/qute-reference#user_tags)

Thank you for pointing this case out! I've made some changes and added a test case, please let me know if I've understood the problem correctly.

[datho7561]

PR seems to be good, but there are test failures: it seems like adding a new user tag to one of the test projects affected a test that counts the number of completion items.