bug#30016: Improve visibility of Process List

[Juri Linkov <juri@linkov.net>]

>> Any hope of a more clever logic that would eliminate the need for
>> arbitrary limits?  Who can know whether there are other users of these
>> facilities which need even wider columns?  E.g., can we display
>> something like
>>
>>    *Async Sh...<1>
>>
>> i.e. make sure the numerical tail is shown?
>
> Yes, this would be the most universal solution.
> And this feature is also necessary in the *Buffer List*
> where *Async Shell Command* buffer names are truncated too.
>
> To support arbitrary formatting in ‘tabulated-list-format’ we could try
> to add a new column property that would allow specifying what suffix
> to leave in truncated columns.  For example, for buffer names it could
> leave the buffer name's unique suffix such as “*Async Sh...<1>”,
> or for directory names the last directory name in the full path,
> e.g. turn “/usr/share/emacs/24.3/lisp/gnus” into “/usr/sha.../gnus”.

It occurred to me that better would be to make tabulated-list columns
resizable.  So if the default column size truncates an important part,
the user could drag the column separator to make it wider, or use
a new key to resize the column, like ‘C-x {’ and ‘C-x }’ are used
to resize the window.

There is one problem: when ‘yes-or-no-p’ is replaced with ‘y-or-n-p’:

  (fset 'yes-or-no-p 'y-or-n-p)

in ~/.emacs it's impossible to switch to the *Process List* buffer
to do this.  Maybe “(y or n)” prompt should allow all standard keys
as in the “(yes or no)” prompt, but as a special case accepting
“y” or “n” without RET?