This fixes some errors which extract_grammar.py reports, when called with
python2.7 src/etc/extract_grammar.py <doc/rust.md
##### Use declarations
~~~~~~~~ {.ebnf .gram}
-use_decl : "pub"? "use" ident [ '=' path
+use_decl : "pub" ? "use" ident [ '=' path
| "::" path_glob ] ;
path_glob : ident [ "::" path_glob ] ?
### Vector expressions
~~~~~~~~{.ebnf .gram}
-vec_expr : '[' "mut"? vec_elems? ']'
+vec_expr : '[' "mut" ? vec_elems? ']'
vec_elems : [expr [',' expr]*] | [expr ',' ".." expr]
~~~~~~~~
"//": "linecomment",
"/*": "openblockcomment",
-"*/": "closeblockcomment"
+"*/": "closeblockcomment",
+"macro_rules": "macro_rules",
+"=>" : "eg",
+".." : "dotdot",
+"," : "comma"
}
lines = []