fix: re-add .log extension to plugin bases logfile name (#546)

Author: marceldev89

lua/plenary/log.lua

@@ -79,8 +79,10 @@ local unpack = unpack or table.unpack
 log.new = function(config, standalone)
   config = vim.tbl_deep_extend("force", default_config, config)
 
-  local outfile =
-    vim.F.if_nil(config.outfile, Path:new(vim.api.nvim_call_function("stdpath", { "cache" }), config.plugin).filename)
+  local outfile = vim.F.if_nil(
+    config.outfile,
+    Path:new(vim.api.nvim_call_function("stdpath", { "cache" }), config.plugin .. ".log").filename
+  )
 
   local obj
   if standalone then