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/sin

@@ -11,10 +11,13 @@ TYPES
     return	number
 
 DESCRIPTION
-    Calculate the sine of x to a multiple of eps with error less in
+    Calculate the trigonometric sine of x to a multiple of eps with error less in
     absolute value than .75 * eps.
 
 EXAMPLE
+    ; print sin(1/2), sin(5/7), sin(42/7)
+    0.47942553860420300027 0.6550778971785185742 -0.27941549819892587281
+
     ; print sin(1, 1e-5), sin(1, 1e-10), sin(1, 1e-15), sin(1, 1e-20)
     0.84147 0.8414709848 0.841470984807896 0.84147098480789650665
 
@@ -22,12 +25,9 @@ EXAMPLE
     9.1545-4.16891i 9.1544991469-4.16890696i
 
     ; pi = pi(1e-20)
-    ; print sin(pi/6, 1e-10), sin(pi/2, 1e-10), sin(pi, 1e-10)
+    ; print sin(pi/6), sin(pi/2), sin(pi)
     0.5 1 0
 
-    ; print sin(1/2), sin(5/7), sin(42/7)
-    0.47942553860420300027 0.6550778971785185742 -0.27941549819892587281
-
 LIMITS
     0 < eps < 1
 
@@ -38,8 +38,10 @@ LINK LIBRARY
 SEE ALSO
     cos, tan, cot, sec, 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) 1999,2021,2023  Landon Curt Noll