TextFile :: indent - Indent formatted text

The function allows indenting formatted text. Indents are inserted for formatted text after writing a line break (lineBreak), i.e. the function will increase the indent level. The current indenting value is calculated from indentSize multiplied by indent level, which gives the number of spaces to be inserted.

In order to reduce indent level, unindent() may be called.

The function is supported for formatted text processing, only. Any other kind of text processing will cause an exception.