bug#46621: Copy line

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 22 Feb 2021 17:04:02 +0000
> From: Gregory Heytings <gregory@heytings.org>
> 
> My 2 cents: a typical case where this could be useful is:
> 
> switch (foobar) {
> case long_enum_value_name_a: printf ("a"); break;
> case long_enum_value_name_b: printf ("b"); break;
> case long_enum_value_name_c: printf ("c"); break;
> case long_enum_value_name_d: printf ("d"); break;
> case long_enum_value_name_e: printf ("e"); break;
> case long_enum_value_name_f: printf ("f"); break;
> case long_enum_value_name_g: printf ("g"); break;
> case long_enum_value_name_h: printf ("h"); break;
> case long_enum_value_name_i: printf ("i"); break;
> default: printf ("?"); break;
> }

Here's how I'd type this:

  case long_enum_value_name_a: printf ("a"); break;
  c M-/ DEL b : p M-/ ("b"); b M-/
  c M-/ DEL c : p M-/ ("c"); b M-/
  c M-/ M-/ DEL d : p M-/ ("d"); b M-/

etc.  (And if the series are indeed longer than a couple of lines, a
rare case indeed, then a keyboard macro is in order.)