Fix a typo in doc/Makefile.am preventing the documentation to build.

doc/Makefile.am

@@ -29,7 +29,7 @@ if BUILD_DOCUMENTATION
 if USE_LATEX
 	rm -f latex/libcaca.tex latex/libcaca.pdf
 	mv latex/refman.tex latex/libcaca.tex
-	sed 's/setlength{/renewcommand{/' latex/neercs.tex \
+	sed 's/setlength{/renewcommand{/' latex/libcaca.tex \
 	  | sed 's/.*usepackage.*times.*//' > latex/refman.tex
 	cd latex && $(MAKE) $(AM_CFLAGS) refman.pdf || (cat refman.log; exit 1)
 	mv latex/refman.pdf latex/libcaca.pdf