DOC: edit scipy.optimize.show_options parameters

Add maxfun parameter to output of parameters for L-BFGS-B. Fix maxiter
description. See ticket 3760.

closes gh-3760
Merge pull request #3776 from Jacobcvt12/lbfgsb-show-options

DOC: edit scipy.optimize.show_options parameters
DOC: removed repetitive text, fixes #3782
Merge pull request #3783 from gregcaporaso/issue-3782

DOC: removed repetitive text, fixes #3782