[MINOR][DOCS] Use ASCII characters when possible in PySpark documentation

[HyukjinKwon]

What changes were proposed in this pull request?

This PR replaces the non-ASCII characters to ASCII characters when possible in PySpark documentation

Why are the changes needed?

To avoid unnecessarily using other non-ASCII characters which could lead to the issue such as #32047 or #22782

Does this PR introduce any user-facing change?

Virtually no.

How was this patch tested?

Found via (Mac OS):

# In Spark root directorycd python
pcregrep --color='auto' -n "[\x80-\xFF]"`git ls-files .`

[HyukjinKwon]

This doesn't have to be backported. So I intentionally separate it from #32047.

[SparkQA]

Test build #136890 has finished for PR 32048 at commit 8911f1d.

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

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/41467/

[SparkQA]

Kubernetes integration test status failure
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/41467/

[MaxGekk]

+1, LGTM. Merging to master.
Thank you @HyukjinKwon .

[HyukjinKwon]

Thx max!