Add links to DLMF and add some more plots (#1370)

Also adjust Alternatives tagging.

Author: rocky

mathics/builtin/patterns/composite.py

@@ -31,7 +31,7 @@ class Alternatives(InfixOperator, PatternObject):
 
     <dl>
       <dt>'Alternatives'[$p_1$, $p_2$, ..., $p_i$]
-      <dt>'$p_1$ | $p_2$ | ... | $p_i$'
+      <dt>$p_1$ '|' $p_2$ '|' ... '|' $p_i$
       <dd>is a pattern that matches any of the patterns $p_1$, $p_2$, \
         ...., $p_i$.
     </dl>

mathics/builtin/specialfns/bessel.py

@@ -1,5 +1,9 @@
 """
 Bessel and Related Functions
+
+See also <url>
+:Chapter 10 Bessel Functions in the Digital Library of Mathematical Functions:
+https://dlmf.nist.gov/10</url>.
 """
 
 import mpmath
@@ -82,6 +86,9 @@ class AiryAiPrime(MPMathFunction):
     Numeric evaluation:
     >> AiryAiPrime[0.5]
      = -0.224911
+
+    >> Plot[AiryAiPrime[x], {x, -10, 10}]
+     = -Graphics-
     """
 
     mpmath_name = ""
@@ -196,16 +203,19 @@ class AiryBiPrime(MPMathFunction):
     Numeric evaluation:
     >> AiryBiPrime[0.5]
      = 0.544573
+
+    >> Plot[AiryBiPrime[x], {x, -10, 2}]
+     = -Graphics-
     """
 
     mpmath_name = ""
-    sympy_name = "airybiprime"
 
     rules = {
         "Derivative[1][AiryBiPrime]": "(#1 AiryBi[#1])&",
     }
 
     summary_text = "derivative of the Airy's function Bi"
+    sympy_name = "airybiprime"
 
     def get_mpmath_function(self, args):
         return lambda x: mpmath.airybi(x, derivative=1)

mathics/builtin/specialfns/elliptic.py

@@ -8,6 +8,10 @@
 finding the arc length of an ellipse.
 
 These functions often are used in cryptography to encode and decode messages.
+
+See also <url>
+:Chapter 19 Elliptic Integrals in the Digital Library of Mathematical Functions:
+https://dlmf.nist.gov/19</url>.
 """
 
 import sympy

mathics/builtin/specialfns/erf.py

@@ -2,6 +2,10 @@
 
 """
 Error Function and Related Functions
+
+See also <url>
+:Chapter 7 Error Functions, Dawson's and Fresnel Integrals:
+https://dlmf.nist.gov/7</url>.
 """
 
 

mathics/builtin/specialfns/gamma.py

@@ -1,5 +1,9 @@
 """
 Gamma and Related Functions
+
+See also <url>
+:Chapter 5 Gamma Function in the Digital Library of Mathematical Functions:
+https://dlmf.nist.gov/5</url>.
 """
 
 import sys