Minor edits to Parameters doc page. (#7500)
Minor edits to Parameters doc page. (#7500)

* bost -> both

* doc improvement

* use original filename

* syntax highlight false

* missed a few highlights
dmlc/xgboost,dmlc/xgboost,dmlc/xgboost,dmlc/xgboost,dmlc/xgboost,dmlc/xgboost