fix links in entry HTML files other than index.html

Fixed internal links in entry HTML files other than index.html.

Removed links to markdown files that otherwise used to
generate HTML files other than index.html.

Ran `make gen_other_html` to perform the above.

1998/schweikh1/macos.html

@@ -155,7 +155,7 @@ command line tools installed which can be done like:</p>
 the entry, the alternate version has also removed this limitation despite <code>gcc</code>
 existing (though it’s <code>clang</code>) in macOS.</p>
 <p>Now as far as how this works if you look at the code of
-<a href="schweikh1.c">schweikh1.c</a>, on line 55 you’ll see a funny command (this goes for
+<a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1998/schweikh1/schweikh1.c">schweikh1.c</a>, on line 55 you’ll see a funny command (this goes for
 the alternate version as well but a bit different).</p>
 <p>Now the key is two magic numbers, one (two times) on a different line shortly below the
 string and the other a couple lines further below.</p>

1998/schweikh1/macos.md

@@ -28,7 +28,7 @@ the entry, the alternate version has also removed this limitation despite `gcc`
 existing (though it's `clang`) in macOS.
 
 Now as far as how this works if you look at the code of
-[schweikh1.c](schweikh1.c), on line 55 you'll see a funny command (this goes for
+[schweikh1.c](%%REPO_URL%%/1998/schweikh1/schweikh1.c), on line 55 you'll see a funny command (this goes for
 the alternate version as well but a bit different).
 
 Now the key is two magic numbers, one (two times) on a different line shortly below the