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.

1992/imc/README.md

@@ -1,17 +1,17 @@
 ## To build:
 
 ```sh
-make all
+    make all
 ```
 
 
 ## To use:
 
 ```sh
-# text mode
-./imc -text
+    # text mode
+    ./imc -text
 
-./imc
+    ./imc
 ```
 
 
@@ -20,7 +20,7 @@ make all
 To see a number of options and configurations:
 
 ```sh
-./try.sh
+    ./try.sh
 ```
 
 
@@ -125,26 +125,26 @@ raster size; not a good idea!).
 The options of this program are:
 
 ```
--centre x y  (float x,y) Centre the picture at x+iy in the complex
-			 plane (default x=0 y=0)
+    -centre x y  (float x,y) Centre the picture at x+iy in the complex
+			     plane (default x=0 y=0)
 
 
--factor f    (float f)   Use f pixels per unit of the plane (default
-			 f=x/4 where x is the width)
+    -factor f    (float f)   Use f pixels per unit of the plane (default
+			     f=x/4 where x is the width)
 
 
--julia  x y  (float x,y) Draw a julia set. Use x+iy as the constant
-			 to add after squaring (default x=0 y=0)
+    -julia  x y  (float x,y) Draw a julia set. Use x+iy as the constant
+			     to add after squaring (default x=0 y=0)
 
--limit  l    (int l)     Use l iterations maximum (default l=128)
+    -limit  l    (int l)     Use l iterations maximum (default l=128)
 
--mask   m    (int m)     Use m as a mask in deciding the colour of each
-			 pixel (see below) (default m=1)
+    -mask   m    (int m)     Use m as a mask in deciding the colour of each
+			     pixel (see below) (default m=1)
 
--size   x y  (int x,y)   Produce an x-by-y output (default for raster
-			 x=768 y=768; default for text x=63 y=23)
+    -size   x y  (int x,y)   Produce an x-by-y output (default for raster
+			     x=768 y=768; default for text x=63 y=23)
 
--text                    Produce text instead of raster.
+    -text                    Produce text instead of raster.
 ```
 
 The colour of each point is determined by taking the bitwise AND of the
@@ -165,8 +165,8 @@ standard error to indicate its progress (one dot per pixel line).
 Here are a couple of good pictures to draw:
 
 ```sh
-./imc -s 512,512 -f 600000 -l 512 -m 16 -c.00805,.74274 > screen1.ras
-./imc -s512,512 -j-.523,-.535 > screen2.ras
+    ./imc -s 512,512 -f 600000 -l 512 -m 16 -c.00805,.74274 > screen1.ras
+    ./imc -s512,512 -j-.523,-.535 > screen2.ras
 ```