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/coversin

@@ -19,8 +19,8 @@ DESCRIPTION
 	coversin(x) = 1 - sin(x)
 
 EXAMPLE
-    ; print coversin(0.2), coversin(3/7), coversin(-31)
-    0.80133066920493878454 0.58442814500694799193 0.59596235467693499395
+    ; print coversin(1/2), coversin(5/7), coversin(42/7)
+    0.52057446139579699973 0.3449221028214814258 1.27941549819892587281
 
     ; print coversin(1, 1e-5), coversin(1, 1e-10), coversin(1, 1e-15), coversin(1, 1e-20)
     0.15853 0.1585290152 0.158529015192104 0.15852901519210349335
@@ -29,8 +29,8 @@ EXAMPLE
     -8.1545+4.16891i -8.1544991469+4.16890696i
 
     ; pi = pi(1e-20)
-    ; print coversin(pi/6, 1e-10), coversin(pi/2, 1e-10), coversin(pi, 1e-10), coversin(3*pi/2, 1e-10)
-    0.5 0 1 2
+    ; print coversin(pi/6), coversin(pi/2), coversin(pi)
+    0.5 0 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, vercos, covercos
+    aversin, acoversin, avercos, acovercos
+    haversin, hacoversin, havercos, hacovercos
+    ahaversin, hacoversin, havercos, ahacovercos
     epsilon
 
 ## Copyright (C) 2023  Landon Curt Noll