fix and improve trigonometric help files

The trigonometric file files have had several bug fixed.

The EXAMPLE sections of trigonometric file have
been made consistent.

Added these new help files in anticipation of
the code for these new (i.e., to be written) builtin functions:

    hacovercos hacoversin havercos haversin
    ahacovercos ahacoversin ahavercos ahaversin

help/sec

@@ -11,7 +11,7 @@ TYPES
     return	real
 
 DESCRIPTION
-    Calculate the secant of x to a multiple of eps, with error less
+    Calculate the trigonometric secant of x to a multiple of eps, with error less
     in absolute value than .75 * eps.
 
     This function is equivalent to:
@@ -19,6 +19,9 @@ DESCRIPTION
 	sec(x) = 1 / cos(x)
 
 EXAMPLE
+    ; print sec(1/2), sec(5/7), sec(42/7)
+    1.13949392732454912231 1.3235192673191814545 1.04148192659510767648
+
     ; print sec(1, 1e-5), sec(1, 1e-10), sec(1, 1e-15), sec(1, 1e-20)
     1.85082 1.8508157177 1.850815717680926 1.85081571768092561791
 
@@ -26,11 +29,10 @@ EXAMPLE
     ~-0.04167497639869547021+~0.09061109101765280898i ~-0.04167496441100888150+~0.09061113719571288336i
 
     ; pi = pi(1e-20)
-    ; print 1e-10), sec(pi/6, 1e-10), sec(pi/3, 1e-10), sec(pi, 1e-10)
-    1.1547005384 2 -1
+    ; print sec(pi/6), sec(pi/2), sec(pi)
+    1.15470053837925152902 756606132568153667453.84481533280934425956 -1
 
-    ; print sec(1/2), sec(5/7), sec(42/7)
-    1.13949392732454912231 1.3235192673191814545 1.04148192659510767648
+    ; # NOTE: The huge value for sec(pi/2) is because pi, as calculated, is not exact.
 
 LIMITS
     0 < eps < 1
@@ -42,8 +44,10 @@ LINK LIBRARY
 SEE ALSO
     sin, cos, tan, cot, csc
     asin, acos, atan, acot, asec, acsc
-    versin, coversin, vercos, avercos
-    aversin, acoversin, covercos, acovercos
+    versin, coversin, vercos, covercos
+    aversin, acoversin, avercos, acovercos
+    haversin, hacoversin, havercos, hacovercos
+    ahaversin, hacoversin, havercos, ahacovercos
     epsilon
 
 ## Copyright (C) 1999,2023  Landon Curt Noll