fix bin/sort.gitignore.sh and bin/sgi.sh

We added ._.DS_Store to `.gitignore`, and generalized the `/archive/historic/`
year sub-directories into a single pattern line.

We fix `bin/sgi.sh` to properly sort, canonically, `.gitignore` files
including `._.DS_Store` lines.  The tool now stories stdin content
into a temporary file, then prints 6 classes of files from the
temporary file to stdout.

Changed `bin/sgi.sh` VERSION from "1.1.3 2024-08-18"
to "1.2 2024-09-05".

Fixed a bug in `bin/sort.gitignore.sh` that prevented it from
finding the `bin/sgi.sh` tool.

Changed `bin/sort.gitignore.sh` VERSION from "1.1.8 2024-07-28"
to "1.2 2024-09-05".

Performed `make sort_gitignore` to test the above under macOS.

NOTE: The above canonically sorted:

- 2004/hibachi/.gitignore
- 2005/mynx/.gitignore
- 2011/vik/.gitignore
- 2013/dlowe/.gitignore
- 2020/otterness/.gitignore

.gitignore

@@ -1,35 +1,10 @@
 #
 # sort with: bin/sgi.sh
+._.DS_Store
 2024
 .DS_Store
 /NOTES
-/archive/historic/1984
-/archive/historic/1985
-/archive/historic/1986
-/archive/historic/1987
-/archive/historic/1988
-/archive/historic/1989
-/archive/historic/1990
-/archive/historic/1991
-/archive/historic/1992
-/archive/historic/1993
-/archive/historic/1994
-/archive/historic/1995
-/archive/historic/1996
-/archive/historic/1998
-/archive/historic/2000
-/archive/historic/2001
-/archive/historic/2004
-/archive/historic/2005
-/archive/historic/2006
-/archive/historic/2011
-/archive/historic/2012
-/archive/historic/2013
-/archive/historic/2014
-/archive/historic/2015
-/archive/historic/2018
-/archive/historic/2019
-/archive/historic/2020
+/archive/historic/[12][0-9][0-9][0-9]
 .auth.json
 author_wins.csv
 author_wins.numbers