remove trailing blanks in markdown files

We used this command to find markdown files with trailing whitespace.

```sh
find . -name '*.md' -print0 | xargs -0 grep -E -l '[[:space:]][[:space:]]*$'
```

After removal, we did a `make www`.

1992/buzzard.2/buzzard.2.README.md

@@ -3,7 +3,7 @@
 [third](third)				    implementation of THIRD in FIRST\
 [help.th](help.th)			    online listing of THIRD primitives\
 
-	
+
 # FIRST demos:
 
 Use  `./first < <demo>`.

1992/buzzard.2/buzzard.2.design.html

@@ -311,7 +311,7 @@ entirely different subject.)</p>
 
 test
 
-( The result of running this program should be: 
+( The result of running this program should be:
 Hello
 )</code></pre>
 <h2 id="section-2-motivating-third">Section 2: Motivating THIRD</h2>
@@ -711,7 +711,7 @@ scan the input until it finds a <code>)</code>, and exit.</p>
 : &lt;= 1 + &lt; ;
 : &gt;= swap &lt;= ;
 
-: inci 
+: inci
   r @ 1 -   ( get the pointer to i )
   inc       ( add one to it )
   r @ 1 - @     ( find the value again )
@@ -810,7 +810,7 @@ fix-::
 : dump _dump ;
 
 : # . cr ;
-  
+
 : var &lt;build , does&gt; ;
 : constant &lt;build , does&gt; @ ;
 : array &lt;build allot does&gt; + ;

1992/buzzard.2/buzzard.2.design.md

@@ -250,7 +250,7 @@ different subject.)
 
 test
 
-( The result of running this program should be: 
+( The result of running this program should be:
 Hello
 )
 ```
@@ -377,7 +377,7 @@ terminate a compilation, and turn control over to the
 command-mode handler.  We don't have one, so all we want
 `;` to do for now is compile `exit` at the end of the
 current word.  To do this we'll need several other words.
-		
+
 Swap by writing out the top two elements into temps, and
 then reading them back in the other order.
 
@@ -429,7 +429,7 @@ at that memory location.
 
 ```
 
-`,` is a standard FORTH word.  It should write the top of 
+`,` is a standard FORTH word.  It should write the top of
 stack into the dictionary, and advance the pointer
 
 ```
@@ -541,7 +541,7 @@ top of the return stack.
 
 Now, we want to do `if`.  To do this, we need to convert
 values to boolean values.  The next few words set this
-up.	
+up.
 
 `minus` gives us unary negation.
 
@@ -793,7 +793,7 @@ exit.
 : <= 1 + < ;
 : >= swap <= ;
 
-: inci 
+: inci
   r @ 1 - 	( get the pointer to i )
   inc		( add one to it )
   r @ 1 - @ 	( find the value again )
@@ -892,7 +892,7 @@ fix-::
 : dump _dump ;
 
 : # . cr ;
-  
+
 : var <build , does> ;
 : constant <build , does> @ ;
 : array <build allot does> + ;