fix many internal links

Fixed a number of internal links that need to
go to the GitHub site.

Ran `make www` to perform the above.

2019/yang/README.md

@@ -209,7 +209,7 @@ Verified to work and compiles without warnings on these environments:
 
 I tried really hard to make `prog.c` fit in a 80x25 terminal without wrapping.
 If I were not constrained by space, I would have made an ASCII art out of it.
-[violet.c](violet.c) is that program, and also comes with the minor benefit of
+[violet.c](%%REPO_URL%%/2019/yang/violet.c) is that program, and also comes with the minor benefit of
 supporting lines longer than a million columns depending on `sizeof(int)`.
 
 Violet is named after [Violet

2019/yang/index.html

@@ -496,7 +496,7 @@ feeds (preserved) and tabs (expanded to 8 spaces).</p>
 <h3 id="full-version">Full version</h3>
 <p>I tried really hard to make <code>prog.c</code> fit in a 80x25 terminal without wrapping.
 If I were not constrained by space, I would have made an ASCII art out of it.
-<a href="violet.c">violet.c</a> is that program, and also comes with the minor benefit of
+<a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2019/yang/violet.c">violet.c</a> is that program, and also comes with the minor benefit of
 supporting lines longer than a million columns depending on <code>sizeof(int)</code>.</p>
 <p>Violet is named after <a href="https://en.wikipedia.org/wiki/Violet_Evergarden">Violet
 Evergarden</a> in the story with