small tweak for hyp2f1 doc

Author: AllinCottrell

doc/commands/gretl_functions_en.xml

@@ -6373,23 +6373,23 @@
       </fnargs>
       <description>
 	<para context="notex">
-	  Returns the Gauss hypergeometric function for the real
+	  Returns the Gaussian hypergeometric function for the real
 	  argument <argname>x</argname>. Valid values for
-	  <argname>x</argname> are between &minus;1 and 1
-	  (inclusive). This function is very general, and reduces to a
-	  simpler function is some special cases, such as for example
+	  <argname>x</argname> are in the closed interval [&minus;1, 1].
+	  This function is very general, and reduces to a
+	  simpler function in some special cases, such as for example
 	  <math>-</math>log(<math>1-x</math>)/<math>x</math> for
 	  <math>a=b=1</math> and <math>c=2</math>. See
 	  <url>https://en.wikipedia.org/wiki/Hypergeometric_function</url>
 	  for more details.
 	</para>
 	<para context="tex">
-	  Returns the Gauss hypergeometric function
+	  Returns the Gaussian hypergeometric function
 	  <math>{}_2F_1(a,b;c;z) = \sum_{n=0}^\infty \frac{(a)_n
-	  (b)_n}{(c)_n} \frac{z^n}{n!}.</math> for real argument
+	  (b)_n}{(c)_n} \frac{z^n}{n!}</math> for real argument
 	  <argname>x</argname>. Valid values for <argname>x</argname>
-	  are between <math>-1</math> and 1 (inclusive). This function
-	  is very general, and reduces to a simpler function is some
+	  are in the closed interval [&minus;1, 1]. This function
+	  is very general, and reduces to a simpler function in some
 	  special cases, such as for example
 	  <math>-\frac{\log(1-x)}{x}</math> for <math>a=b=1</math> and
 	  <math>c=2</math>. See