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.

1990/theorem/README.md

@@ -1,7 +1,7 @@
 ## To build:
 
 ```sh
-make all
+    make all
 ```
 
 
@@ -10,7 +10,7 @@ make all
 The current status of this entry is:
 
 ```
-STATUS: INABIAF - please **DO NOT** fix
+    STATUS: INABIAF - please **DO NOT** fix
 ```
 
 For more detailed information see [1990 theorem bugs](../../bugs.html#1990_theorem).
@@ -19,24 +19,24 @@ For more detailed information see [1990 theorem bugs](../../bugs.html#1990_theor
 ## To use:
 
 ```sh
-./theorem expression x1 x2 h y1
+    ./theorem expression x1 x2 h y1
 ```
 
 where:
 
 ```
-expression - function f(x,y)  (see below)
-x1 - start of interval
-x2 - end of interval
-h - step size
-y1 - initial value  (y(x1) == y1)
+    expression - function f(x,y)  (see below)
+    x1 - start of interval
+    x2 - end of interval
+    h - step size
+    y1 - initial value  (y(x1) == y1)
 ```
 
 
 ## Try:
 
 ```sh
-./try.sh
+    ./try.sh
 ```
 
 
@@ -53,7 +53,7 @@ The 'expression' `f(x,y)` is any function of `x` and `y` with the
 operators:
 
 ```
-+	-	*	/	^
+    +	-	*	/	^
 ```
 
 The symbol `^` is the power operator.  Note that it only supports
@@ -63,24 +63,24 @@ left to right.  (i.e., parenthesis aren't supported).
 Try running the program with the following args:
 
 ```sh
-./theorem y 0 1 0.1 1
-./theorem 1/x 1 2 0.1 0
-./theorem 'x^2/y+x' 0 1 0.1 6
+    ./theorem y 0 1 0.1 1
+    ./theorem 1/x 1 2 0.1 0
+    ./theorem 'x^2/y+x' 0 1 0.1 6
 ```
 
 But wait, there is more!  You also get, free of charge, a
 reversing filter!  Try:
 
 ```sh
-./theorem -r 0 0 0 0 < theorem.c > sorter.c
+    ./theorem -r 0 0 0 0 < theorem.c > sorter.c
 ```
 
 Still not impressed?  The author throws in for free, a
 sort program! Try:
 
 ```sh
-make sorter
-ls | ./sorter
+    make sorter
+    ls | ./sorter
 ```
 
 This program is safe for home use as well.  The author has
@@ -88,17 +88,17 @@ included a safety feature in case you misplace the original
 program source:
 
 ```sh
-./sorter -r 0 0 0 0 < sorter.c > theorem_bkp.c
+    ./sorter -r 0 0 0 0 < sorter.c > theorem_bkp.c
 ```
 
 And finally, as a special offer to users of this entry,
 the author provides a Fibonacci sequence generator!  Try:
 
 ```sh
-./sorter 0 0 0 0 < theorem.c > fibonacci.c
-make fibonacci
-./fibonacci 1 1
-./fibonacci 2 1
+    ./sorter 0 0 0 0 < theorem.c > fibonacci.c
+    make fibonacci
+    ./fibonacci 1 1
+    ./fibonacci 2 1
 ```
 
 NOTE: if the two args passed to `fibonacci` and `theorem_bkp` add to 0 it will