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.

1991/ant/README.md

@@ -1,7 +1,7 @@
 ## To build:
 
 ```sh
-make all
+    make all
 ```
 
 There is an [alternate version](#alternate-code) that might feel a bit more
@@ -11,7 +11,7 @@ familiar to vi(m) users.
 ## To use:
 
 ```sh
-./ant some_file
+    ./ant some_file
 ```
 
 NOTE: the file must already exist and not specifying any arg will make the
@@ -21,13 +21,13 @@ program exit without doing anything.
 ## Try:
 
 ```sh
-make hill
-./ant hill
+    make hill
+    ./ant hill
 ```
 
 ```sh
-make mole
-./ant mole
+    make mole
+    ./ant mole
 ```
 
 
@@ -47,7 +47,7 @@ rest was unchanged.
 ### Alternate build:
 
 ```sh
-make alt
+    make alt
 ```