Revert sql-expression-schema.md

Author: beliefer

sql/core/src/test/resources/sql-functions/sql-expression-schema.md

@@ -346,4 +346,4 @@
 | org.apache.spark.sql.catalyst.expressions.xml.XPathList | xpath | SELECT xpath('<a><b>b1</b><b>b2</b><b>b3</b><c>c1</c><c>c2</c></a>','a/b/text()') | struct<xpath(<a><b>b1</b><b>b2</b><b>b3</b><c>c1</c><c>c2</c></a>, a/b/text()):array<string>> |
 | org.apache.spark.sql.catalyst.expressions.xml.XPathLong | xpath_long | SELECT xpath_long('<a><b>1</b><b>2</b></a>', 'sum(a/b)') | struct<xpath_long(<a><b>1</b><b>2</b></a>, sum(a/b)):bigint> |
 | org.apache.spark.sql.catalyst.expressions.xml.XPathShort | xpath_short | SELECT xpath_short('<a><b>1</b><b>2</b></a>', 'sum(a/b)') | struct<xpath_short(<a><b>1</b><b>2</b></a>, sum(a/b)):smallint> |
-| org.apache.spark.sql.catalyst.expressions.xml.XPathString | xpath_string | SELECT xpath_string('<a><b>b</b><c>cc</c></a>','a/c') | struct<xpath_string(<a><b>b</b><c>cc</c></a>, a/c):string> |
+| org.apache.spark.sql.catalyst.expressions.xml.XPathString | xpath_string | SELECT xpath_string('<a><b>b</b><c>cc</c></a>','a/c') | struct<xpath_string(<a><b>b</b><c>cc</c></a>, a/c):string> |