[SPARK-33251][FOLLOWUP][PYTHON][DOCS][MINOR] Adjusts returns PrefixSpan.findFrequentSequentialPatterns
[SPARK-33251][FOLLOWUP][PYTHON][DOCS][MINOR] Adjusts returns PrefixSpan.findFrequentSequentialPatterns

### What changes were proposed in this pull request?

Changes

    pyspark.sql.dataframe.DataFrame

to

    :py:class:`pyspark.sql.DataFrame`

### Why are the changes needed?

Consistency (see https://github.com/apache/spark/pull/30285#pullrequestreview-526764104).

### Does this PR introduce _any_ user-facing change?

User will see shorter reference with a link.

### How was this patch tested?

`dev/lint-python` and manual check of the rendered docs.

Closes #30313 from zero323/SPARK-33251-FOLLOW-UP.

Authored-by: zero323 <0f81822ec43dc7f424811d0a422871ea124aa3dd@gmail.com>
Signed-off-by: Huaxin Gao <b1011540267ee7fe5a02243ad09c007ca1860809@us.ibm.com>

shaneknapp/spark,nchammas/spark,holdenk/spark,witgo/spark,taroplus/spark,ueshin/apache-spark,zero323/spark,BryanCutler/spark,milliman/spark,HyukjinKwon/spark,BryanCutler/spark,HyukjinKwon/spark,witgo/spark,dongjoon-hyun/spark,taroplus/spark,zzcclp/spark,xuanyuanking/spark,nchammas/spark,rednaxelafx/apache-spark,holdenk/spark,holdenk/spark,shuangshuangwang/spark,HyukjinKwon/spark,nchammas/spark,srowen/spark,jiangxb1987/spark,srowen/spark,gengliangwang/spark,WeichenXu123/spark,wangmiao1981/spark,ueshin/apache-spark,apache/spark,zero323/spark,chuckchen/spark,vinodkc/spark,vinodkc/spark,vinodkc/spark,BryanCutler/spark,holdenk/spark,wangyum/spark,srowen/spark,milliman/spark,vinodkc/spark,rednaxelafx/apache-spark,apache/spark,wangyum/spark,maropu/spark,taroplus/spark,milliman/spark,wangyum/spark,cloud-fan/spark,maropu/spark,gengliangwang/spark,HyukjinKwon/spark,holdenk/spark,hvanhovell/spark,JoshRosen/spark,srowen/spark,shaneknapp/spark,nchammas/spark,witgo/spark,JoshRosen/spark,dongjoon-hyun/spark,wangyum/spark,maropu/spark,shuangshuangwang/spark,WeichenXu123/spark,cloud-fan/spark,jiangxb1987/spark,HyukjinKwon/spark,WeichenXu123/spark,hvanhovell/spark,milliman/spark,dongjoon-hyun/spark,rednaxelafx/apache-spark,chuckchen/spark,zero323/spark,xuanyuanking/spark,jiangxb1987/spark,zero323/spark,hvanhovell/spark,rednaxelafx/apache-spark,cloud-fan/spark,zero323/spark,wangmiao1981/spark,maropu/spark,dongjoon-hyun/spark,witgo/spark,gengliangwang/spark,mahak/spark,shuangshuangwang/spark,hvanhovell/spark,JoshRosen/spark,milliman/spark,cloud-fan/spark,JoshRosen/spark,hvanhovell/spark,jiangxb1987/spark,dongjoon-hyun/spark,HyukjinKwon/spark,shuangshuangwang/spark,maropu/spark,HyukjinKwon/spark,dongjoon-hyun/spark,shuangshuangwang/spark,dongjoon-hyun/spark,shaneknapp/spark,mahak/spark,apache/spark,WeichenXu123/spark,holdenk/spark,JoshRosen/spark,taroplus/spark,maropu/spark,wangyum/spark,hvanhovell/spark,zzcclp/spark,gengliangwang/spark,zzcclp/spark,gengliangwang/spark,witgo/spark,apache/spark,milliman/spark,ueshin/apache-spark,mahak/spark,wangmiao1981/spark,ueshin/apache-spark,milliman/spark,taroplus/spark,xuanyuanking/spark,shaneknapp/spark,wangyum/spark,witgo/spark,shaneknapp/spark,srowen/spark,maropu/spark,srowen/spark,jiangxb1987/spark,xuanyuanking/spark,shuangshuangwang/spark,mahak/spark,xuanyuanking/spark,shaneknapp/spark,vinodkc/spark,nchammas/spark,WeichenXu123/spark,nchammas/spark,wangmiao1981/spark,JoshRosen/spark,gengliangwang/spark,vinodkc/spark,ueshin/apache-spark,holdenk/spark,rednaxelafx/apache-spark,BryanCutler/spark,WeichenXu123/spark,zzcclp/spark,zzcclp/spark,srowen/spark,jiangxb1987/spark,vinodkc/spark,jiangxb1987/spark,zzcclp/spark,cloud-fan/spark,xuanyuanking/spark,mahak/spark,nchammas/spark,mahak/spark,ueshin/apache-spark,chuckchen/spark,WeichenXu123/spark,apache/spark,zero323/spark,apache/spark,ueshin/apache-spark,witgo/spark,mahak/spark,hvanhovell/spark,taroplus/spark,chuckchen/spark,taroplus/spark,rednaxelafx/apache-spark,chuckchen/spark,xuanyuanking/spark,BryanCutler/spark,wangmiao1981/spark,wangmiao1981/spark,shaneknapp/spark,wangmiao1981/spark,zero323/spark,zzcclp/spark,JoshRosen/spark,BryanCutler/spark,BryanCutler/spark,cloud-fan/spark,cloud-fan/spark,chuckchen/spark,shuangshuangwang/spark,chuckchen/spark,gengliangwang/spark,rednaxelafx/apache-spark,wangyum/spark,apache/spark