auto merge of rust-lang#15865 : jamesrhurst/rust/ctags-regex, r=alexcrichton

Previously the implementation detection regex would detect
`impl fmt::Show for MyStruct` as `fmt`. Now it will be detected as
`fmt::Show for MyStruct`. Implementations such as `impl MyStruct` will
still be detected as `MyStruct`.

Author: bors

src/etc/ctags.rust

@@ -7,5 +7,5 @@
 --regex-Rust=/^[ \t]*(pub[ \t]+)?mod[ \t]+([a-zA-Z0-9_]+)/\2/m,modules,module names/
 --regex-Rust=/^[ \t]*(pub[ \t]+)?static[ \t]+([a-zA-Z0-9_]+)/\2/c,consts,static constants/
 --regex-Rust=/^[ \t]*(pub[ \t]+)?trait[ \t]+([a-zA-Z0-9_]+)/\2/t,traits,traits/
---regex-Rust=/^[ \t]*(pub[ \t]+)?impl([ \t\n]+<.*>)?[ \t]+([a-zA-Z0-9_]+)/\3/i,impls,trait implementations/
+--regex-Rust=/^[ \t]*(pub[ \t]+)?impl([ \t\n]*<[^>]*>)?[ \t]+(([a-zA-Z0-9_:]+)[ \t]*(<[^>]*>)?[ \t]+(for)[ \t]+)?([a-zA-Z0-9_]+)/\4 \6 \7/i,impls,trait implementations/
 --regex-Rust=/^[ \t]*macro_rules![ \t]+([a-zA-Z0-9_]+)/\1/d,macros,macro definitions/