### What changes were proposed in this pull request?
This PR intends to fix typos in the sub-modules:
* `bin`
* `core`
* `docs`
* `external`
* `mllib`
* `repl`
* `pom.xml`
Split per srowen https://github.com/apache/spark/pull/30323#issuecomment-728981618
NOTE: The misspellings have been reported at 706a726f87 (commitcomment-44064356)
### Why are the changes needed?
Misspelled words make it harder to read / understand content.
### Does this PR introduce _any_ user-facing change?
There are various fixes to documentation, etc...
### How was this patch tested?
No testing was performed
Closes#30530 from jsoref/spelling-bin-core-docs-external-mllib-repl.
Authored-by: Josh Soref <jsoref@users.noreply.github.com>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
### What changes were proposed in this pull request?
This PR adds the SQL standard command - `SET TIME ZONE` to the current default time zone displacement for the current SQL-session, which is the same as the existing `set spark.sql.session.timeZone=xxx'.
All in all, this PR adds syntax as following,
```
SET TIME ZONE LOCAL;
SET TIME ZONE 'valid time zone'; -- zone offset or region
SET TIME ZONE INTERVAL XXXX; -- xxx must in [-18, + 18] hours, * this range is bigger than ansi [-14, + 14]
```
### Why are the changes needed?
ANSI compliance and supply pure SQL users a way to retrieve all supported TimeZones
### Does this PR introduce _any_ user-facing change?
yes, add new syntax.
### How was this patch tested?
add unit tests.
and locally verified reference doc
Closes#29064 from yaooqinn/SPARK-32272.
Authored-by: Kent Yao <yaooqinn@hotmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
