check for any ASCII tabs anywhere in markdown files

Clarified and simplified the request to not use ASCII tabs within
markdown file content.

Added _guidelines_ to `next/guidelines.md` about not using ASCII
tab characters in markdown files while stating that is just fine
to use ASCII tabs in non-markdown files and C code.

The `make tab_check` rule now simply checks for ASCII tabs within
markdown files, except `markdown.md` where they are required to
serve as examples of what not to do.

Perform `make quick_www` to perform the above and test under macOS.

Perform `make www` to perform the above and test under macOS.

next/guidelines.html

@@ -933,6 +933,11 @@ and state:</p>
 given enough time and memory. If the value is not a proper integer, the program
 will insult a fish named Eric, even if such a fish does not exist.</p>
 </blockquote>
+<p><strong><code>|</code></strong> We <strong>DISLIKE</strong> the use of use ASCII tab characters in markdown files, such as in the required <code>remarks.md</code> file.</p>
+<p><strong><code>|</code></strong> We don’t mind the use ASCII tab characters in your C code. Feel free to use ASCII tab characters if that suits your obfuscation needs. If is perfectly <strong>OK</strong> to use tab characters elsewhere in your submission, just not in markdown files as this tends complicate and annoys us when be comes to rendering your markdown content.</p>
+<p><strong><code>|</code></strong> If you do use ASCII tab characters in your non-markdown files, be aware that some people may use tab stop that is different than the common 8 character tab stop.</p>
+<p><strong><code>|</code></strong> We enjoy a reading <code>remarks.md</code> files, especially if they contain useful, informative, and even humorous content about your entry.</p>
+<p><strong><code>|</code></strong> We <strong>RECOMMEND</strong> you put a reasonable amount effort into the content of the <code>remarks.md</code> file: it is a required for for a reason. :-)</p>
 <h1 id="abusing-the-rules">ABUSING THE RULES:</h1>
 <p>Legal abuse of the <a href="rules.html">IOCCC rules</a> is somewhat encouraged. Legal rule abuse
 may involve, but is not limited to, doing things that are technically allowed by

next/guidelines.md

@@ -752,6 +752,18 @@ and state:
 given enough time and memory.  If the value is not a proper integer, the program
 will insult a fish named Eric, even if such a fish does not exist.
 
+**`|`**   We **DISLIKE** the use of use ASCII tab characters in markdown files, such as in the required `remarks.md` file.
+
+**`|`**   We don't mind the use ASCII tab characters in your C code.  Feel free to use ASCII tab characters if that suits your obfuscation needs.  If is perfectly **OK** to use tab characters elsewhere in your submission, just not in markdown files as this tends complicate and annoys us when be comes to rendering your markdown content.
+
+**`|`**   If you do use ASCII tab characters in your non-markdown files, be aware that some people may use tab stop that is different than the common 8 character tab stop.
+
+**`|`**   We enjoy a reading `remarks.md` files, especially if they contain useful, informative, and even humorous content about your entry.
+
+**`|`**   We **RECOMMEND** you put a reasonable amount effort into the content of the `remarks.md` file: it is a required for for a reason.  :-)
+
+
+
 
 # ABUSING THE RULES: