[re.alg.replace] Add whitespace and bullets to make this paragraph more

readable and disambiguate the binding of the "Then calls" clause in the third
sentence.

Fixes #279.

Author: zygoloid

source/regex.tex

@@ -3494,22 +3494,46 @@
 \pnum
 \indexlibrary{\idxcode{format_no_copy}}%
 \indexlibrary{\idxcode{format_first_only}}%
-\effects  Constructs a \tcode{regex_iterator} object \tcode{i}
-as if by \tcode{regex_iterator<BidirectionalIterator, charT, traits>
-i(first, last, e, flags)}, and uses \tcode{i} to enumerate through all
+\effects
+Constructs a \tcode{regex_iterator} object \tcode{i}
+as if by
+\begin{codeblock}
+regex_iterator<BidirectionalIterator, charT, traits> i(first, last, e, flags)
+\end{codeblock}
+and uses \tcode{i} to enumerate through all
 of the matches \tcode{m} of type \tcode{match_results<BidirectionalIterator>} 
-that occur within the sequence \range{first}{last}. If no such
+that occur within the sequence \range{first}{last}.
+If no such
 matches are found and \tcode{!(flags \&
-regex_constants \colcol format_no_copy)} then calls \tcode{out = std::copy(first,
-last, out)}.  If any matches are found then, for each such match,
-if \tcode{!(flags \& regex_constants::format_no_copy)}, calls 
-\tcode{out = std\colcol{}copy(m.prefix().first, m.prefix().second, \brk{}out)}, and
-then calls \tcode{out = m.format(out, fmt, flags)}
+regex_constants::format_no_copy)} then calls
+\begin{codeblock}
+out = std::copy(first, last, out)
+\end{codeblock}
+If any matches are found then, for each such match:
+\begin{itemize}
+\item
+If \tcode{!(flags \& regex_constants::format_no_copy)}, calls 
+\begin{codeblock}
+out = std::copy(m.prefix().first, m.prefix().second, out)
+\end{codeblock}
+\item
+Then calls
+\begin{codeblock}
+out = m.format(out, fmt, flags)
+\end{codeblock}
 for the first form of the function and
-\tcode{out = m.format(out,} \tcode{fmt, fmt + char_traits<charT>::length(fmt), flags)} for the second. Finally, if such a match
-is found and \tcode{!(flags \& regex_constants \colcol format_no_copy)},
-calls \tcode{out = std::\brk{}copy(last_m.suffix().first, last_m.suffix().second,
-out)} where \tcode{last_m} is a copy of the last match
+\begin{codeblock}
+out = m.format(out, fmt, fmt + char_traits<charT>::length(fmt), flags)
+\end{codeblock}
+for the second.
+\end{itemize}
+Finally, if such a match
+is found and \tcode{!(flags \& regex_constants::format_no_copy)},
+calls
+\begin{codeblock}
+out = std::copy(last_m.suffix().first, last_m.suffix().second, out)
+\end{codeblock}
+where \tcode{last_m} is a copy of the last match
 found. If \tcode{flags \& regex_constants::format_first_only} 
 is non-zero then only the first match found is replaced.