[SPARK-16287][HOTFIX][BUILD][SQL] Fix annotation argument needs to be a constant

## What changes were proposed in this pull request?

Build fix for [SPARK-16287][SQL] Implement str_to_map SQL function that has introduced this compilation error:

```
/Users/jacek/dev/oss/spark/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypeCreator.scala:402: error: annotation argument needs to be a constant; found: "_FUNC_(text[, pairDelim, keyValueDelim]) - Creates a map after splitting the text ".+("into key/value pairs using delimiters. ").+("Default delimiters are \',\' for pairDelim and \':\' for keyValueDelim.")
    "into key/value pairs using delimiters. " +
                                              ^
```

## How was this patch tested?

Local build

Author: Jacek Laskowski <jacek@japila.pl>

Closes #14315 from jaceklaskowski/build-fix-complexTypeCreator.

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

@@ -397,11 +397,11 @@ case class CreateNamedStructUnsafe(children: Seq[Expression]) extends Expression
 /**
  * Creates a map after splitting the input text into key/value pairs using delimiters
  */
+// scalastyle:off line.size.limit
 @ExpressionDescription(
-  usage = "_FUNC_(text[, pairDelim, keyValueDelim]) - Creates a map after splitting the text " +
-    "into key/value pairs using delimiters. " +
-    "Default delimiters are ',' for pairDelim and ':' for keyValueDelim.",
+  usage = "_FUNC_(text[, pairDelim, keyValueDelim]) - Creates a map after splitting the text into key/value pairs using delimiters. Default delimiters are ',' for pairDelim and ':' for keyValueDelim.",
   extended = """ > SELECT _FUNC_('a:1,b:2,c:3',',',':');\n map("a":"1","b":"2","c":"3") """)
+// scalastyle:on line.size.limit
 case class StringToMap(text: Expression, pairDelim: Expression, keyValueDelim: Expression)
   extends TernaryExpression with CodegenFallback with ExpectsInputTypes {