Minor fixes in the man page.

ChangeLog

@@ -1,3 +1,7 @@
+2019-06-06         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* awk.1: Fix a typo, minor edits.
+
 2019-06-05         Arnold D. Robbins     <arnold@skeeve.com>
 
 	* b.c (relex): Count parentheses and treat umatched right paren

awk.1

@@ -209,7 +209,7 @@ or length of
 if no argument.
 .TP
 .B rand
-random number on (0,1)
+random number on (0,1).
 .TP
 .B srand
 sets seed for
@@ -217,7 +217,7 @@ sets seed for
 and returns the previous seed.
 .TP
 .B int
-truncates to an integer value
+truncates to an integer value.
 .TP
 \fBsubstr(\fIs\fB, \fIm\fR [\fB, \fIn\^\fR]\fB)\fR
 the
@@ -228,9 +228,8 @@ that begins at position
 .I m 
 counted from 1.
 If no
-.IR m ,
-use the rest of the string
-.I 
+.IR n ,
+use the rest of the string.
 .TP
 .BI index( s , " t" )
 the position in