feat(LSP): Modify the way a virtual env is located

Changed the hard-coded virtual environment directory name used to look
for Python related binaries to whatever directory is defined in the
`VIRTUAL_ENV` environment variable.  That variable's value is more
reliable, even more when Python virtual environments are located in a
central location, not near the repository.

nvim/lua/lsp/server_settings/pylsp.lua

@@ -35,8 +35,8 @@ local pylsp_settings = {
     },
 }
 
-local venv_dir = vim.fn.finddir(".venv/", vim.fn.expand("%:p:h") .. ";")
-if venv_dir ~= "" then
+local venv_dir = vim.env.VIRTUAL_ENV
+if venv_dir ~= nil then
   local python_exec = vim.fn.findfile("python", venv_dir .. "/bin;")
   if python_exec ~= "" then
     pylsp_settings.plugins.jedi = {environment = python_exec}