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.

1993/rince/README.md

@@ -13,8 +13,6 @@ England
 make all
 ```
 
-[Yusuke Endoh](/winners.html#Yusuke_Endoh) supplied a patch to get this to work
-in modern systems. Thank you Yusuke!
 
 ## To run:
 
@@ -26,6 +24,7 @@ where:
 	
 `[cabbage]` is a CABBAGE description file  (default: `rince.c`)
 
+
 ## Judges' remarks:
     
 The author has provided several CABBAGE files for your amusement:
@@ -210,6 +209,7 @@ There is no 'end of game' checking method. Hence games like Sokoban rely
 on the user to decide when they have had enough. Also, there is no quit
 mechanism other than control C.
 
+
 ## Copyright and CC BY-SA 4.0 License:
 
 This file is Copyright (c) 2023 by Landon Curt Noll.  All Rights Reserved.