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.

2015/endoh4/README.md

@@ -1,7 +1,7 @@
 ## To build:
 
 ```sh
-make
+    make
 ```
 
 
@@ -12,14 +12,14 @@ code](#alternate-code) below for details.
 ## To use:
 
 ```sh
-./prog <a number of arguments>
+    ./prog <a number of arguments>
 ```
 
 
 ## Try:
 
 ```sh
-./try.sh
+    ./try.sh
 ```
 
 
@@ -33,7 +33,7 @@ Dogon](../../authors.html#Gil_Dogon); it is the author's original entry.
 ### Alternate build:
 
 ```sh
-make alt
+    make alt
 ```
 
 
@@ -55,14 +55,14 @@ experiment with numbers that have more or larger factors?
 Visual factorization 1-liner.  Try:
 
 ```sh
-gcc -o prog prog.c
-./prog @
-./prog @ @
-./prog @ @ @
-./prog @ @ @ @
-./prog @ @ @ @ @ @
-./prog @ @ @ @ @ @ @ @
-./prog @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
+    gcc -o prog prog.c
+    ./prog @
+    ./prog @ @
+    ./prog @ @ @
+    ./prog @ @ @ @
+    ./prog @ @ @ @ @ @
+    ./prog @ @ @ @ @ @ @ @
+    ./prog @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
 ```
 
 Inspired by [Animated Factorization