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/covercos

@@ -14,13 +14,13 @@ DESCRIPTION
     Calculate the coversed trigonometric cosine of x to a multiple of eps with error less in
     absolute value than .75 * eps.
 
-    This function is sometimes called cvc, is equivalent to:
+    This function is sometimes called cvc, or covercosine, is equivalent to:
 
 	covercos(x) = 1 + sin(x)
 
 EXAMPLE
-    ; print covercos(0.2), covercos(3/7), covercos(-31)
-    1.19866933079506121546 1.41557185499305200807 1.40403764532306500605
+    ; print covercos(1/2), covercos(5/7), covercos(42/7)
+    1.47942553860420300027 1.6550778971785185742 0.72058450180107412719
 
     ; print covercos(1, 1e-5), covercos(1, 1e-10), covercos(1, 1e-15), covercos(1, 1e-20)
     1.84147 1.8414709848 1.841470984807896 1.84147098480789650665
@@ -29,8 +29,8 @@ EXAMPLE
     10.1545-4.16891i 10.1544991469-4.16890696i
 
     ; pi = pi(1e-20)
-    ; print covercos(pi/6, 1e-10), covercos(pi/2, 1e-10), covercos(pi, 1e-10), covercos(3*pi/2, 1e-10)
-    1.5 2 1 0
+    ; print covercos(pi/6), covercos(pi/2), covercos(pi)
+    1.5 2 1
 
 LIMITS
     0 < eps < 1
@@ -42,8 +42,10 @@ LINK LIBRARY
 SEE ALSO
     sin, cos, tan, cot, sec, csc
     asin, acos, atan, acot, asec, acsc
-    versin, coversin, vercos, avercos
-    aversin, acoversin, covercos, acovercos
+    versin, coversin, vercos
+    aversin, acoversin, avercos, acovercos
+    haversin, hacoversin, havercos, hacovercos
+    ahaversin, hacoversin, havercos, ahacovercos
     epsilon
 
 ## Copyright (C) 2023  Landon Curt Noll