Update usage to place text-wrap on label

Editor assessment

The subject states the usage correction exactly: text-wrap belongs on the label element rather than elsewhere, which resolves a concrete documentation misdirection. docs(label) is accurate and the scope exact. The 'closes ionic-team/ionic-docs#467' footer is well-formed in the cross-repository convention and anchors the correction to its report, giving the change a traceable origin. No body is needed for this realignment. Wording is compact and clean. Complete for its purpose.