[MRG+1] Spelling mistake in Feature Extraction documentation (#8763)

* task: Fixed the minor change in code from svr to svm merging back to main branch http://scikit-learn.org/dev/modules/generated/sklearn.model_selection.GridSearchCV.html#sklearn.model_selection.GridSearchCV done on: Mar 13 2017 14:30 IST

* issue#8761: Fixed the code with spelling mistake Spelling mistake in
Feature Extraction documentation #8761