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.

1990/tbr/README.md

@@ -19,17 +19,10 @@ US
 make all
 ```
 
-[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) fixed this to work with
-modern compilers; `exit(3)` returns void but the function was used in a binary
-expression so this wouldn't even compile. Cody also changed the code to use
-`fgets()` instead of `gets()` so one would not get a warning about the use of
-`gets()` at linking time or execution, the latter case causing confusing output
-due to the warning being interspersed with the program's output. Thank you Cody
-for your assistance!
-
 For the original version with `gets()` see the [archive
 tarball](/archive/archive-1990.tar.bz2).
 
+
 ## To run:
 
 ```sh
@@ -42,6 +35,7 @@ NOTE: globs do not work with this entry. Why?
 NOTE: `exit` does not work and neither does `logout`. To exit try sending ctrl-d
 or ctrl-c (or kill it from another terminal :-) ).
 
+
 ## Try:
 
 ```sh
@@ -57,8 +51,8 @@ vi tbr.c
 What happens if you try using `cd -` to return to previous directory? What about
 `cd` with no args?
 
-## Judges' remarks:
 
+## Judges' remarks:
 
 This program touches on a well known Unix utility, the 6th edition Bourne Shell
 (`/bin/sh`), whose original source was considered to be extremely obfuscated by
@@ -86,6 +80,7 @@ e(x){x<0?write(2,"?\n$ "-x/4,2),x+1||(exit(1),0):5;}
 It has the `exit()` returns void fix but not the `gets()` to `fgets()` fix
 applied.
 
+
 ## Author's remarks:
 
 ### Rot13:
@@ -144,6 +139,7 @@ applied.
     Gurer vf whfg bar reebe zrffntr, gur dhrfgvba znex, ohg url, gung'f
     nyy rq qbrf gbb.
 
+
 ## Copyright and CC BY-SA 4.0 License:
 
 This file is Copyright (c) 2023 by Landon Curt Noll.  All Rights Reserved.