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.

2004/arachnid/README.md

@@ -1,7 +1,7 @@
 ## To build:
 
 ```sh
-make
+    make
 ```
 
 There is an alt version for rogue players, vi(m) users and Dvorak typist (i.e.
@@ -12,20 +12,20 @@ code](#alternate-code) below.
 ## To use:
 
 ```sh
-./arachnid [mazefile]
+    ./arachnid [mazefile]
 ```
 
 
 ## Try:
 
 ```sh
-./arachnid arachnid.txt
+    ./arachnid arachnid.txt
 ```
 
 and then try:
 
 ```sh
-./arachnid arachnid.c
+    ./arachnid arachnid.c
 ```
 
 Navigation is through the use of the `wasd` inverted-T formation on
@@ -42,7 +42,7 @@ instead.
 ### Alternate build:
 
 ```sh
-make alt
+    make alt
 ```
 
 
@@ -81,7 +81,7 @@ explorers out there.
 ### Usage
 
 ```sh
-./arachnid [mazefile]
+    ./arachnid [mazefile]
 ```
 
 You can explore the maze using the `w`,`a`,`s`, and `d` keys.