touchgfx::Unicode::strncpy() method

@fn static uint16_t Unicode::strncpy(UnicodeChar* RESTRICT dst, const UnicodeChar* RESTRICT src, uint16_t maxchars); Copy a string to a destination buffer, UnicodeChar to UnicodeChar version. Copy a string to a destination buffer, UnicodeChar to UnicodeChar version. Stops if it encounters a zero-termination, in which case the zero-termination is included in the destination string. Otherwise copies maxchars. @warning If there is no null-termination among the first n UnicodeChars of src, the string placed in destination will NOT be zero-terminated!