[SPARK-14402][HOTFIX] Fix ExpressionDescription annotation

## What changes were proposed in this pull request?

Fix for the error introduced in https://github.com/apache/spark/commit/c59abad052b7beec4ef550049413e95578e545be:

```
/Users/jacek/dev/oss/spark/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala:626: error: annotation argument needs to be a constant; found: "_FUNC_(str) - ".+("Returns str, with the first letter of each word in uppercase, all other letters in ").+("lowercase. Words are delimited by white space.")
    "Returns str, with the first letter of each word in uppercase, all other letters in " +
                                                                                          ^
```

## How was this patch tested?

Local build

Author: Jacek Laskowski <jacek@japila.pl>

Closes #12192 from jaceklaskowski/SPARK-14402-HOTFIX.

1 files changed, 3 insertions, 3 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
index b6ea03cd5c..7e0e7a833b 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
@@ -622,9 +622,9 @@ case class FormatString(children: Expression*) extends Expression with ImplicitC
  * Words are delimited by whitespace.
  */
 @ExpressionDescription(
-  usage = "_FUNC_(str) - " +
-    "Returns str, with the first letter of each word in uppercase, all other letters in " +
-    "lowercase. Words are delimited by white space.",
+  usage =
+   """_FUNC_(str) - Returns str with the first letter of each word in uppercase.
+     All other letters are in lowercase. Words are delimited by white space.""",
   extended = "> SELECT initcap('sPark sql');\n 'Spark Sql'")
 case class InitCap(child: Expression) extends UnaryExpression with ImplicitCastInputTypes {