[SPARK-34881][SQL][FOLLOW-UP] Use multiline string for TryCast' expression description

[HyukjinKwon]

What changes were proposed in this pull request?

This PR fixes JDK 11 compilation failed:

/home/runner/work/spark/spark/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/TryCast.scala:35: error: annotation argument needs to be a constant; found: "_FUNC_(expr AS type) - Casts the value `expr` to the target data type `type`. ".+("This expression is identical to CAST with configuration `spark.sql.ansi.enabled` as ").+("true, except it returns NULL instead of raising an error. Note that the behavior of this ").+("expression doesn\'t depend on configuration `spark.sql.ansi.enabled`.")
    "true, except it returns NULL instead of raising an error. Note that the behavior of this " +

For whatever reason, it doesn't know that the string is actually a constant. This PR simply switches it to multi-line style (which is actually more correct).

Reference:

spark/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/ApproximatePercentile.scala

Lines 53 to 57 in bd0990e

	usage = """
	_FUNC_(col, percentage [, accuracy]) - Returns the approximate `percentile` of the numeric
	column `col` which is the smallest value in the ordered `col` values (sorted from least to
	greatest) such that no more than `percentage` of `col` values is less than the value
	or equal to that value. The value of percentage must be between 0.0 and 1.0. The `accuracy`

Why are the changes needed?

To recover the build.

Does this PR introduce any user-facing change?

No, dev-only.

How was this patch tested?

CI in this PR

[SparkQA]

Kubernetes integration test unable to build dist.

exiting with code: 1
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[SparkQA]

Kubernetes integration test starting
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[gengliangwang]

Thanks, merging to master

[SparkQA]

Kubernetes integration test status failure
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/41380/

[SparkQA]

Test build #136792 has finished for PR 32019 at commit 14b5968.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #136797 has finished for PR 32019 at commit f83d4e2.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.