fix: Do not fail on trigger_events’ pattern

[Ltrlg]

The following example configuration in the README.md:

{
  trigger_events = {
    immediate_save = {
      { "BufLeave", pattern = {"*.c", "*.h"} }
    }
  }
}

results in

Failed to run `config` for auto-save.nvim                                                             
                                                                                                      
...lazy/auto-save.nvim/lua/auto-save/utils/autocommands.lua:38: Invalid 'event': '*.c'                
                                                                                                      
# stacktrace:                                                                                         
  - /auto-save.nvim/lua/auto-save/utils/autocommands.lua:38 _in_ **create_autocmd_for_trigger_events**
  - /auto-save.nvim/lua/auto-save/init.lua:114 _in_ **on**                                            
  - /auto-save.nvim/lua/auto-save/init.lua:171 _in_ **setup**     
  - ~/.config/nvim/init.lua                               

[Neovim v0.10.2 from Arch / auto-save 5fbcaac with Lazy.nvim]

This commit fixes the nvim_create_autocmd loop to not confuse the pattern = … entry with an event name.

[Ltrlg]

Looks like I misread the README.md, sorry.