builtin-apply: rename "whitespace" variables and fix styles

builtin-apply: rename "whitespace" variables and fix styles

The variables were somewhat misnamed.

 * "What to do when whitespace errors are detected" is now called
   "ws_error_action" (used to be called "new_whitespace");

 * The constants to denote the possible actions are "nowarn_ws_error",
   "warn_on_ws_error", "die_on_ws_error", and "correct_ws_error".  The
   last one used to be "strip_whitespace", but we correct whitespace
   error in indent (SP followed by HT) and "strip" is not quite an
   accurate name for it.

Other than the renaming of variables and constants, there is no
functional change in this patch.  While we are at it, it also fixes
overly long lines and multi-line comment styles (which of course do
not affect the generated code at all).

Signed-off-by: Junio C Hamano <gitster@pobox.com>