[SPARK-26224][SQL][PYTHON][R][FOLLOW-UP] Add notes about many projects in withColumn at SparkR and PySpark as well

[HyukjinKwon]

What changes were proposed in this pull request?

This is a followup of #23285. This PR adds the notes into PySpark and SparkR documentation as well.

While I am here, I revised the doc a bit to make it sound a bit more neutral

How was this patch tested?

Manually built the doc and verified.

[HyukjinKwon]

cc @cloud-fan and @mgaido91

[felixcheung]

LGTM. is this also applicable to withColumnRenamed?

[SparkQA]

Test build #104184 has finished for PR 24272 at commit 9f6c9ae.

• This patch fails due to an unknown error code, -9.
• This patch merges cleanly.
• This patch adds no public classes.

[HyukjinKwon]

retest this please

[HyukjinKwon]

The reported case was a usecase making sense with withColumn but I am not sure with withColumnRenamed ... Hope we can handle that differently later.

[mgaido91]

LGTM, thanks @HyukjinKwon . I don't think withColumnRenamed is used by users in big for loops as I have seen for withColumn, so I think it is fine not to handle it. Thanks.

[SparkQA]

Test build #104190 has finished for PR 24272 at commit 9f6c9ae.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[HyukjinKwon]

retest this please

[SparkQA]

Test build #104206 has finished for PR 24272 at commit 9f6c9ae.

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

[HyukjinKwon]

Thanks, @felixcheung, @mgaido91, @srowen and @viirya.

Merged to master.