Check and Fix outdated urls

[cdietrich]

Check and Fix outdated urls

• javadocs (also check if the variables are used)
• use eclipse.dev consistently (no eclipse.org no xtend-lang.org no xtext.org)
• check outdated community links

[cdietrich]

cc @LorenzoBettini this is the issue for the cleanup

[cdietrich]

first round of changes merged as new domain is live now
=> next step is to run broken link detector again

[Lokeshc123]

@cdietrich can i work on this issue?

[cdietrich]

@Lokeshc123 yes please
(current live website is on published branch)

[Lokeshc123]

ok sure
can you pls elaborate a bit about what to do i am new open-source developer and very excited to work
I

[cdietrich]

• clone this repo, check out published branch
• check eclipse.dev/Xtext eclipse/Xtext/xtend + subpages for broken links
• fix them
• open pr against published branch (needs commit to be signed of and eclipse eca signed https://www.eclipse.org/legal/ECA.php)