fix more broken markdown links

We fix more markdown links in markdown files that refer to files
internally to the web site.

Added tmp tools to find and print various markdown links:

* `tmp/md-links.sh` - print all markdown links
* `tmp/md-token-links.sh` - print all markdown links that start with a **%%TOKEN%%**
* `tmp/md-local-links.sh` - print all markdown links to a local file
* `tmp/md-link-paths.sh` - print local file paths referenced in markdown links

Fixed a number of markdown formatting problems with `thanks-for-help.md`.
Fixed markdown links to files in `thanks-for-help.md`.  Improved
heading levels in `thanks-for-help.md`, and made entry sections consistent.

Changed all markdown links that end in "))" to end in a better way.

Explained in `markdown.md` why we are avoiding markdown links that
end in "))".

Ran `make www` to perform the above.

TODO: Fix stuff we broke by mistake doing the above.

TODO: Fix more broken markdown links.

2004/anonymous/README.md

@@ -93,8 +93,8 @@ transcription to standard output as a [portable
 graymap](https://en.wikipedia.org/wiki/Netpbm#PGM_example) (PGM) file.
 
 The specific transcription mode is the [Black
-Speech](https://www.glyphweb.com/arda/b/blackspeech.html) ([Tengwar
-mode](https://www.glyphweb.com/arda/t/tengwar.html)), as
+Speech](https://www.glyphweb.com/arda/b/blackspeech.html)
+([Tengwar](https://www.glyphweb.com/arda/t/tengwar.html) mode), as
 used in the inscription on the [One
 Ring](https://www.glyphweb.com/arda/o/onering.html). The program handles the
 following digraphs:

2004/anonymous/index.html

@@ -454,8 +454,8 @@ argument text into Tolkien’s Elvish letters, and writes the
 transcription to standard output as a <a href="https://en.wikipedia.org/wiki/Netpbm#PGM_example">portable
 graymap</a> (PGM) file.</p>
 <p>The specific transcription mode is the <a href="https://www.glyphweb.com/arda/b/blackspeech.html">Black
-Speech</a> (<a href="https://www.glyphweb.com/arda/t/tengwar.html">Tengwar
-mode</a>), as
+Speech</a>
+(<a href="https://www.glyphweb.com/arda/t/tengwar.html">Tengwar</a> mode), as
 used in the inscription on the <a href="https://www.glyphweb.com/arda/o/onering.html">One
 Ring</a>. The program handles the
 following digraphs:</p>

2004/gavare/README.md

@@ -114,7 +114,7 @@ although the compiler gives it special meaning) and no preprocessor
 directives.
 
 This program is a small
-[ray-tracer](https://en.wikipedia.org/wiki/Ray_tracing_(graphics)). The first
+[ray-tracer](https://en.wikipedia.org/wiki/Ray_tracing_(graphics)). The first
 line of the source code may be modified if you want the resulting image to be of
 some other resolution than the predefined. The `A` value is an anti-alias
 factor. Setting it to `1` disables the anti-aliasing feature which makes the

2004/gavin/README.md

@@ -102,8 +102,8 @@ well as the judges' remarks below plus [gavin.html](gavin.html).
 ## Judges' remarks:
 
 Over the years, we've seen a program that immediately dumps core if executed on
-the "wrong" architectures (e.g., [1984/mullender](../../1984/mullender/index.html)) and a
-program that dumps core after a while (e.g., [2001/bellard](../../2001/bellard/index.html)).
+the "wrong" architectures (e.g., [1984/mullender](../../1984/mullender/index.html) entry) and a
+program that dumps core after a while (e.g., [2001/bellard](../../2001/bellard/index.html) entry).
 This entry will happily compile and execute on most any architecture - the trick
 is that the result, to be useful, must be produced (and can only be enjoyed) on
 a particular architecture.  We have not decided yet whether to disallow this for

2004/gavin/index.html

@@ -441,8 +441,8 @@ generated are the same names. See <a href="#to-use">to use</a> and <a href="#try
 well as the judges’ remarks below plus <a href="gavin.html">gavin.html</a>.</p>
 <h2 id="judges-remarks">Judges’ remarks:</h2>
 <p>Over the years, we’ve seen a program that immediately dumps core if executed on
-the “wrong” architectures (e.g., <a href="../../1984/mullender/index.html">1984/mullender</a>) and a
-program that dumps core after a while (e.g., <a href="../../2001/bellard/index.html">2001/bellard</a>).
+the “wrong” architectures (e.g., <a href="../../1984/mullender/index.html">1984/mullender</a> entry) and a
+program that dumps core after a while (e.g., <a href="../../2001/bellard/index.html">2001/bellard</a> entry).
 This entry will happily compile and execute on most any architecture - the trick
 is that the result, to be useful, must be produced (and can only be enjoyed) on
 a particular architecture. We have not decided yet whether to disallow this for

2004/jdalbec/README.md

@@ -47,7 +47,7 @@ which line it is on.
     make alt
 ```
 
-The macro `Ag` ([silver](https://en.wikipedia.org/wiki/Silver)) controls how
+The macro [Ag](https://en.wikipedia.org/wiki/Silver) controls how
 many number of lines to print on a line. Set at default to 11 protons, salt, if
 you wish to make it silver, 47 (a prime) protons, do:
 

2004/jdalbec/index.html

@@ -416,7 +416,7 @@ that don’t end up having too many line breaks it also makes it easier to see
 which line it is on.</p>
 <h3 id="alternate-build">Alternate build:</h3>
 <pre><code>    make alt</code></pre>
-<p>The macro <code>Ag</code> (<a href="https://en.wikipedia.org/wiki/Silver">silver</a>) controls how
+<p>The macro <a href="https://en.wikipedia.org/wiki/Silver">Ag</a> controls how
 many number of lines to print on a line. Set at default to 11 protons, salt, if
 you wish to make it silver, 47 (a prime) protons, do:</p>
 <pre><code>    make clobber Ag=47 alt</code></pre>

2004/vik2/README.md

@@ -157,7 +157,7 @@ Then run the program to reveal all prime numbers up to 32 (if you used
 
 I wasn't able to compile the full program which calculates [prime
 numbers](https://en.wikipedia.org/wiki/Prime_number) up to 1024 using GNU `cpp`
-(or any other [pre-processor](https://en.wikipedia.org/wiki/C_preprocessor)) so
+(or any other [pre-processor](https://en.wikipedia.org/wiki/C_preprocessor) tool) so
 I had to write my own. Knowing how the program works it was quite easy to reduce
 the compilation time from several hours to about one second. I also added some
 statistics to my home made pre-processor and I found that calculating prime

2004/vik2/index.html

@@ -504,7 +504,7 @@ work. This will take some time….</p>
 <h3 id="verification">Verification</h3>
 <p>I wasn’t able to compile the full program which calculates <a href="https://en.wikipedia.org/wiki/Prime_number">prime
 numbers</a> up to 1024 using GNU <code>cpp</code>
-(or any other <a href="https://en.wikipedia.org/wiki/C_preprocessor">pre-processor</a>) so
+(or any other <a href="https://en.wikipedia.org/wiki/C_preprocessor">pre-processor</a> tool) so
 I had to write my own. Knowing how the program works it was quite easy to reduce
 the compilation time from several hours to about one second. I also added some
 statistics to my home made pre-processor and I found that calculating prime