improved indentation and whitespace for markdown code blocks

All code blocks in markdown have been intended by at least 4 spaces.

We add `--tab-stop=8` to all `pandoc(1)` executions in order to set
a better tab stop indentation, especially for tab intended code blocks.

Changed `bin/pandoc-wrapper.sh` VERSION from "1.5.3 2024-03-26"
to "1.6 2024-03-31".

Fixed `1991/brnstnd/sorta.README.md` so that the sorta code
is code blocks.

Removed unneeded paragraph group in copyright in `inc/footer.default.html`.

Fixed excess whitespace after list Author on entry `index.html` page.

Changed `bin/output-index-author.sh` VERSION from "1.5.2 2024-03-26"
to "1.6 2024-03-31".

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

TODO: Fix the problem of the initial line of code being extra intended.
TODO: Fix excess whitespace around code that is inline.

2018/endoh1/README.md

@@ -1,14 +1,14 @@
 ## To build:
 
 ```sh
-make
+    make
 ```
 
 
 ## To use:
 
 ```sh
-./prog < textfile > output.gif
+    ./prog < textfile > output.gif
 ```
 
 
@@ -17,7 +17,7 @@ make
 To see the input files and feed them to the program, redirecting to GIF files:
 
 ```sh
-./try.sh
+    ./try.sh
 ```
 
 
@@ -41,8 +41,8 @@ least 2MiB of memory to run in.
 This program generates an animated GIF from a plain text.  Run:
 
 ```sh
-cc -o prog prog.c
-./prog < invisible.txt > invisible.gif
+    cc -o prog prog.c
+    ./prog < invisible.txt > invisible.gif
 ```
 
 Open `invisible.gif` with a GIF viewer that can show animated GIFs and then wait
@@ -52,14 +52,14 @@ letters that leave the mark and ones that do not?
 Other examples:
 
 ```sh
-./prog < golem.txt > golem.gif
-./prog < smily.txt > smily.gif
+    ./prog < golem.txt > golem.gif
+    ./prog < smily.txt > smily.gif
 ```
 
 The program itself has a hidden message.
 
 ```sh
-./prog < prog.c > prog.gif
+    ./prog < prog.c > prog.gif
 ```
 
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