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.

2020/kurdyukov3/README.md

@@ -1,7 +1,7 @@
 ## To build:
 
 ```sh
-make
+    make
 ```
 
 There is an alternate version of this program. See [Alternate
@@ -11,14 +11,14 @@ code](#alternate-code) below.
 ## To use:
 
 ```sh
-./prog
+    ./prog
 ```
 
 
 ## Try:
 
 ```sh
-./try.sh
+    ./try.sh
 ```
 
 
@@ -30,7 +30,7 @@ The alternate version, [prog.alt.c](prog.alt.c), has the main code as a macro.
 ### Alternate build:
 
 ```sh
-make alt
+    make alt
 ```
 
 
@@ -62,7 +62,7 @@ exactly what it says nonetheless.
 Compile and try this:
 
 ```sh
-cat input.txt | ./prog
+    cat input.txt | ./prog
 ```
 
 The program can work with letters that are not represented in English, as long