spelling/grammar fix in dap-terminated-hook docstring (#492)

Fixes two small typos that I ran across when configuring `dap-mode`. Thanks for writing such a cool package!

Author: AdamNiederer

dap-mode.el

@@ -149,7 +149,7 @@ based on DAP protocol category."
 (defcustom dap-terminated-hook nil
   "List of functions to be called after a debug session has been terminated.
 
-The functions will received the debug dession that
+The functions will receive the debug session that
 has been terminated."
   :type 'hook
   :group 'dap-mode)