nvim: add working check for perlls

.config/nvim/lua/my/lsp.lua

@@ -193,12 +193,13 @@ if vim.fn.executable('gopls') > 0 then
     })
 end
 
--- there is no good and fast enough way to check for its existence
-lspconfig.perlls.setup({
-    autostart = false,
-    on_attach = on_attach,
-    capabilities = capabilities
-})
+if vim.fn.glob('/usr/lib64/perl5/vendor_perl/5.*/Perl/LanguageServer.pm') ~= ''
+then
+    lspconfig.perlls.setup({
+        on_attach = on_attach,
+        capabilities = capabilities
+    })
+end
 
 if vim.fn.executable('qml-lsp') > 0 then
     lspconfig.qml_lsp.setup({