To get autocomplete for love2d in neovim (using lua_ls & neovim's plugins), .luarc.json must be put at the root of the project:
{
"$schema": "https://raw.githubusercontent.com/LuaLS/vscode-lua/master/setting/schema.json",
"workspace.library": [
"${3rd}/love2d/library"
]
}workspace.library is used by lua_ls to find definitions files for love2d as suggested here.