[macros, styles] Add \hypertarget to headings (#6516)

This allows forming URLs with a stable label as a fragment and
have PDF viewers jump to the corresponding (sub)clause.

For example: std.pdf#basic.life

source/macros.tex

@@ -64,6 +64,7 @@
 %% Cross-references.
 %%--------------------------------------------------
 \newcommand{\addxref}[1]{%
+ \hypertarget{#1}{}%
  \glossary[xrefindex]{\indexescape{#1}}{(\ref{\indexescape{#1}})}%
 }
 
@@ -92,14 +93,15 @@
 % defines a first-level section whose name is "Scope" and whose short
 % tag is intro.scope.  The square brackets are mandatory.
 \def\Sec#1[#2]#3{%
+\addxref{#2}%
 \ifcase#1\let\s=\chapter\let\l=\clauselabel
       \or\let\s=\section\let\l=\label
       \or\let\s=\subsection\let\l=\label
       \or\let\s=\subsubsection\let\l=\label
       \or\let\s=\paragraph\let\l=\label
       \or\let\s=\subparagraph\let\l=\label
       \fi%
-\s[#3]{#3\hfill[#2]}\l{#2}\addxref{#2}%
+\s[#3]{#3\hfill[#2]}\l{#2}%
 }
 
 % A convenience feature (mostly for the convenience of the Project

source/styles.tex

@@ -87,8 +87,8 @@
 %%--------------------------------------------------
 % set heading style for annexes
 \newcommand{\Annex}[3]{\chapter[#2]{(#3)\protect\\#2\hfill[#1]}\relax\annexlabel{#1}}
-\newcommand{\infannex}[2]{\Annex{#1}{#2}{informative}\addxref{#1}}
-\newcommand{\normannex}[2]{\Annex{#1}{#2}{normative}\addxref{#1}}
+\newcommand{\infannex}[2]{\addxref{#1}\Annex{#1}{#2}{informative}}
+\newcommand{\normannex}[2]{\addxref{#1}\Annex{#1}{#2}{normative}}
 
 %%--------------------------------------------------
 %%  set footnote style