Fix examples

Author: MaxGekk

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala

@@ -450,7 +450,7 @@ case class IntegralDivide(left: Expression, right: Expression) extends DivModLik
     Examples:
       > SELECT 2 _FUNC_ 1.8;
        0.2
-      > SELECT MOD(2, 1.8);
+      > SELECT _FUNC_(2, 1.8);
        0.2
   """)
 case class Remainder(left: Expression, right: Expression) extends DivModLike {

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala

@@ -1097,7 +1097,7 @@ case class TimeAdd(start: Expression, interval: Expression, timeZoneId: Option[S
   usage = "_FUNC_(timestamp, timezone) - Given a timestamp like '2017-07-14 02:40:00.0', interprets it as a time in UTC, and renders that time as a timestamp in the given time zone. For example, 'GMT+1' would yield '2017-07-14 03:40:00.0'.",
   examples = """
     Examples:
-      > SELECT from_utc_timestamp('2016-08-31', 'Asia/Seoul');
+      > SELECT _FUNC_('2016-08-31', 'Asia/Seoul');
        2016-08-31 09:00:00
   """,
   since = "1.5.0",

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala

@@ -1123,7 +1123,7 @@ case class SubstringIndex(strExpr: Expression, delimExpr: Expression, countExpr:
        4
       > SELECT _FUNC_('bar', 'foobarbar', 5);
        7
-      > SELECT POSITION('bar' IN 'foobarbar');
+      > SELECT _FUNC_('bar' IN 'foobarbar');
        4
   """,
   since = "1.5.0")
@@ -1732,9 +1732,9 @@ case class Left(str: Expression, len: Expression, child: Expression) extends Run
     Examples:
       > SELECT _FUNC_('Spark SQL ');
        10
-      > SELECT CHAR_LENGTH('Spark SQL ');
+      > SELECT _FUNC_('Spark SQL ');
        10
-      > SELECT CHARACTER_LENGTH('Spark SQL ');
+      > SELECT _FUNC_('Spark SQL ');
        10
   """,
   since = "1.5.0")