### What changes were proposed in this pull request?
This PR proposes fix the default value in Data Source Option page based on the Scala documentation.
### Why are the changes needed?
Some of the existing default value in Data Source Option page follow the Python documentation, which has `None` as the default value for all options.
### Does this PR introduce _any_ user-facing change?
Yes, the default value in the Data Source Option page is fixed (from `None` to proper default value)
- Before
<img width="361" alt="Screen Shot 2021-06-02 at 6 31 12 PM" src="https://user-images.githubusercontent.com/44108233/120456594-b8719f00-c3d0-11eb-9778-071ab2ba9f45.png">
- After
<img width="562" alt="Screen Shot 2021-06-02 at 6 32 47 PM" src="https://user-images.githubusercontent.com/44108233/120456844-f1117880-c3d0-11eb-9c7c-9dcd66776444.png">
### How was this patch tested?
Manually built the docs and checked one by one.
Closes#32745 from itholic/SPARK-35523.
Lead-authored-by: itholic <haejoon.lee@databricks.com>
Co-authored-by: Haejoon Lee <44108233+itholic@users.noreply.github.com>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
This PR proposes adding more methods to set data source option to `Data Source Option` page for each data source.
For example, Data Source Option page for JSON as below:
- Before
<img width="322" alt="Screen Shot 2021-06-03 at 10 51 54 AM" src="https://user-images.githubusercontent.com/44108233/120574245-eb13aa00-c459-11eb-9f81-0b356023bcb5.png">
- After
<img width="470" alt="Screen Shot 2021-06-03 at 10 52 21 AM" src="https://user-images.githubusercontent.com/44108233/120574253-ed760400-c459-11eb-9008-1f075e0b9267.png">
### Why are the changes needed?
To provide users various options when they set options for data source.
### Does this PR introduce _any_ user-facing change?
Yes, now the document provides more methods for setting options than before, as in above screen capture.
### How was this patch tested?
Manually built the docs and check one by one.
Closes#32757 from itholic/SPARK-35528.
Authored-by: itholic <haejoon.lee@databricks.com>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
Fix [SPARK-34492], add Scala examples to read/write CSV files.
### Why are the changes needed?
Fix [SPARK-34492].
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Build the document with "SKIP_API=1 bundle exec jekyll build", and everything looks fine.
Closes#31827 from twoentartian/master.
Authored-by: twoentartian <twoentartian@hotmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
