; Improve doc strings in textsec.el

; Improve doc strings in textsec.el

* lisp/international/textsec.el (textsec-email-address-suspicious-p)
(textsec-email-address-header-suspicious-p, textsec-scripts)
(textsec-single-script-p, textsec-covering-scripts)
(textsec-restriction-level, textsec-mixed-numbers-p)
(textsec-resolved-script-set)
(textsec-single-script-confusable-p)
(textsec-mixed-script-confusable-p)
(textsec-whole-script-confusable-p)
(textsec-local-address-suspicious-p)
(textsec-bidi-controls-suspicious-p, textsec-name-suspicious-p)
(textsec-suspicious-nonspacing-p): Doc fixes.