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/leo/README.md

@@ -6,15 +6,13 @@ Moscow Centre of SPARC Technology
 89-1-95 Moscow  
 Russia  
 
+
 ## To build:
 
 ```sh
 make all
 ```
 
-[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) fixed this to work with
-modern compilers. Thank you Cody!
-
 
 ## To run:
 
@@ -34,6 +32,7 @@ where:
 
 [colors] is the number of possible colors (1 to 15) (default: 6)
 
+
 ## Judges' remarks:
     
 By default, the number of colors is 6.  You may specify a
@@ -43,6 +42,7 @@ for instructions of how to play.
 We look forward to more entries from the newer members of the 
 International Internet community.
 
+
 ## Author's remarks:
 
 This program plays
@@ -107,6 +107,7 @@ judges-387> ./mind
 40		   # we have guessed the number
 ```
 
+
 ## Copyright and CC BY-SA 4.0 License:
 
 This file is Copyright (c) 2023 by Landon Curt Noll.  All Rights Reserved.