support linked editing

[maxandersen]

when enabling linked editing in vscode I would expect that when editing declarations that references would be renamed.

i.e.

String test = "a great string";
test.upper();

if editing "test" in second line nothing should change, but if linked editing enable editing "test" in first line to i.e. "mystring" the "test.upper()" should change to "mystring.upper()"

[fbricon]

linked editing is currently not supported, but you can use F2 to rename 'test' and it'll work as you expect

[rgrunber]

Closing as a duplicate of https://github.com/eclipse/eclipse.jdt.ls/issues/1919 .