Merge branch 'rs/parse-options-negation-help'

"git cmd -h" learned to signal which options can be negated by listing such options like "--[no-]opt". * rs/parse-options-negation-help: parse-options: simplify usage_padding() parse-options: no --[no-]no-... parse-options: factor out usage_indent() and usage_padding() parse-options: show negatability of options in short help t1502: test option negation t1502: move optionspec help output to a file t1502, docs: disallow --no-help subtree: disallow --no-{help,quiet,debug,branch,message}