Remove dead symbolic links

for i in `find .`; do if (test -h $i); then file $i|grep broken; fi; done

./es/99book.bib: broken symbolic link to `../en/99book.bib'
./es/bookhtml.cfg: broken symbolic link to `../en/bookhtml.cfg'
./es/fixhtml.py: broken symbolic link to `../en/fixhtml.py'
./es/hgbook.css: broken symbolic link to `../en/hgbook.css'
./es/htlatex.book: broken symbolic link to `../en/htlatex.book'

     1.1 --- a/en/examples/hook.msglen	Tue Jul 25 00:18:31 2006 -0700
     1.2 +++ b/en/examples/hook.msglen	Thu May 21 14:26:31 2009 +0800
     1.3 @@ -5,7 +5,7 @@
     1.4  echo '[hooks]' > .hg/hgrc
     1.5  echo 'pretxncommit.msglen = test `hg tip --template {desc} | wc -c` -ge 10' >> .hg/hgrc
     1.6  
     1.7 -#$ name: run
     1.8 +#$ name: go
     1.9  
    1.10  cat .hg/hgrc
    1.11  echo a > a