Describe the bug

Some devfiles have several commands that need to be executed in a precise order to succeed.
Some are named with prefixed numbers that help the user, but some others are not.

For instance:

• angular
• python-django

Che version

• latest
• nightly
• other: please spec

Document the commands that clients should implement and their expected behaviour on https://github.com/eclipse/eclipse.jdt.ls/wiki/JDT-LS-Extensions

Consider the following:

void meth(Closure closure) {
  closure.|
}

When invoking content assist (Ctrl+Space) at |, the methods and properties of groovy.lang.Closure are very low in the list of proposals. This is due to very-well-known type adjustments made within org.codehaus.groovy.eclipse.codeassist.proposals.AbstractGroovyProposal.getRelevanceClass().

Brief feature description

With the user-header from #14 it is now possible to add custom meta information alongside the user-payload. While this makes some functionality easier, it has some drawbacks for the record and replay functionality since there is now some opaque data which might need some adjustment before the replay, e.g. a timestamp. A curated list of known user-header will help th