Escapes text so that the markup parser will parse it verbatim.
Less than, greater than, ampersand, etc. are replaced with the corresponding entities. This function would typically be used when writing out a file to be parsed with the markup parser.
Note that this function doesn't protect whitespace and line endings from being processed according to the XML rules for normalization of line endings and attribute values.
Note also that this function will produce character references in the range of &
x1; ... &
x1f; for all control
sequences except for tabstop, newline and carriage return. The character references in this range are not valid XML 1.0, but they are valid XML
1.1 and will be accepted by the GMarkup parser.
some valid UTF-8 text
a newly allocated string with the escaped text