maint: update .gitignore

doc/.gitignore

@@ -8,27 +8,18 @@
 #/bison.cp
 #/bison.cps
 #/bison.toc
-
-/*~
-/.dirstamp
+*.dvi
+*.ps
 /bison.1
-/bison.dvi
 /bison.help
 /bison.html
 /bison.info
-/bison.info.bak
-/bison.log
-/bison.pdf
-/bison.ps
 /cross-options.texi
 /figs/*.eps
 /figs/*.svg
 /gendocs_template
 /gendocs_template_min
 /gpl-3.0.texi
-/refcard.dvi
-/refcard.log
-/refcard.ps
 /relocatable.texi
 /stamp-vti
 /version.texi