lsp: Improve compatibility with textDocument/hover

Before this commit, only the first item of the contents of the response were shown. This means, e.g. in the case of eclipse.jdt.ls that is returning several MarkedStrings, only the first one is shown. With this commit, all informations that were sent are now shown.

https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#hover