nvim: Extend lsp configuration with multiple declarations

So far if LSP declarations in 'core/languages.lua' were duplicated (e.g.
the 'astro' filetype and the 'vue' filetype both declare the
'typescript' lsp), one would simply overwrite the other. That is fine as
long as there is no custom setup, but if there is one of them is lost.

This commit changes it so that the different configurations extend each
other. The 'latter' one still overwrites the former but this is just
what must happen if there should be conflicting setups. 

May increase loading time slightly.

nvim/.config/nvim/lua/plugins/lsp.lua

@@ -4,7 +4,7 @@ for _, lang in pairs(Languages) do
 		goto continue
 	end
 	for name, conf in pairs(lang.lsp) do
-		servers[name] = conf
+		servers[name] = vim.tbl_deep_extend("force", servers[name] or {}, conf)
 	end
 	::continue::
 end