add notices to those who wish for a greater challenge

We add the following level-3 header to help people identify text
they may wish to skip if they wish for a greater challenge:

```
```

After that notice we add:

```
**If you want a greater challenge, don't read any further**:
just try to understand the program via the source.

If you get stuck, come back and read below for additional hints and information.
```

And sometimes follow with:

```
```

Or sometimes follow with:

```
```

Where the alt code impacts a "greater challenge", we add instead:

```
**If you want a greater challenge, don't read any further**:
just try to understand the program without looking at the Alternate code.

If you get stuck, come back and look at the Alternate code.
```

And where a given command impacts a "greater challenge", we add instead:

```
**If you want a greater challenge, don't read any further**:
just try to understand the program without running the command below.

If you get stuck, come back and run the following command:
```

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

2019/adamovsky/README.md

@@ -254,13 +254,21 @@ were shuffled both for `S` functions and Apply functions in the same way to hide
 the meaning of `f` and `r` prefixes.
 
 
-### Identification spoiler:
+### NOTICE to those who wish for a greater challenge
+
+**If you want a greater challenge, don't read any further**:
+just try to understand the program via the source.
+
+If you get stuck, come back and read below for additional hints and information.
+
+
+### Identification
 
 The alternative build path `make identify` output commemorates a [previous IOCCC
 winning entry][9] which uses similar methods to mess with the size tool.
 
 
-### Judges' spoiler:
+### How this entry works:
 
 It is not a bug, it is a feature. :)
 

2019/adamovsky/index.html

@@ -570,10 +570,14 @@ continuation and exit functions were swapped. The names of <code>S</code> and Ap
 were shuffled both for <code>S</code> functions and Apply functions in the same way to hide
 the meaning of <code>f</code> and <code>r</code> prefixes.</p></li>
 </ul>
-<h3 id="identification-spoiler">Identification spoiler:</h3>
+<h3 id="notice-to-those-who-wish-for-a-greater-challenge">NOTICE to those who wish for a greater challenge</h3>
+<p><strong>If you want a greater challenge, don’t read any further</strong>:
+just try to understand the program via the source.</p>
+<p>If you get stuck, come back and read below for additional hints and information.</p>
+<h3 id="identification">Identification</h3>
 <p>The alternative build path <code>make identify</code> output commemorates a <a href="../../2014/birken/index.html" title="Best use of port 1701">previous IOCCC
 winning entry</a> which uses similar methods to mess with the size tool.</p>
-<h3 id="judges-spoiler">Judges’ spoiler:</h3>
+<h3 id="how-this-entry-works">How this entry works:</h3>
 <p>It is not a bug, it is a feature. :)</p>
 <p>The crash is caused by a stack overflow. Conventional Unlabmda interpreters
 implement the Unlambda execution stack using data structures on the heap. This