move fix thanks a file, update top level html links, rename CONTRIBUTING.md

The fix thank you's have been moved from `README.md` to
`thanks-for-fixes.md`.

**WARNING**: Some mistakes may have been made in doing this.
We presume later changes by others will correct any issues.

The `CONTRIBUTING.md` was renamed `how-to-enter.md`.

A 3rd line of links was added to top level html such as
`contact.html`, `index.html`, `judges.html`, `winners.html`,
and `years.html`.

Improved blank line use in a number (but not all) `README.md` files.

1998/chaos/README.md

@@ -22,9 +22,6 @@ Or you can build this entry without the `halfdelay()` call by:
 make chaos_nohalf
 ```
 
-[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) added a call to
-`endwin()` to restore terminal sanity (echo etc.) when exiting the program.
-Thank you Cody for your assistance!
 
 ## To run:
 
@@ -33,6 +30,7 @@ Thank you Cody for your assistance!
 ./chaos
 ```
 
+
 ## Judge's Comments:
 
 This is the author's first IOCCC entry.  We thought the entry was
@@ -86,6 +84,7 @@ in front, some reflected from the rear) looks really odd.  And it
 sometimes hangs.  So just don't fly through objects.  You'll be
 happier.
 
+
 ## Copyright and CC BY-SA 4.0 License:
 
 This file is Copyright (c) 2023 by Landon Curt Noll.  All Rights Reserved.