a couple TODOs

TODO.md

@@ -6,6 +6,7 @@
     * Could maybe hack it by parsing the source code span and/or code around the span?
 * Types get shown with their canonical name (after resolving all aliases and re-exports) regardless of what the code called them. So you'll see lots of `impl core::...` when the code really wrote `impl std::...` because `std` re-exports lots of things from `core`.
     * Probably not possible to fix this without parsing the source code.
+* It would be nice to show crate versions, but versions are a Cargo thing, not a rustc thing, and so it isn't present in the analysis data anywhere.
 
 # Enhancements
 * format the label of functions to include the signature?
@@ -17,3 +18,4 @@
     * globally is probably a bad idea
     * let users hit F3 or something to continue to the next match
 * Allow some way to specify a particular rust toolchain / target. Currently we just run `rustc` and `cargo` and you get whatever the default is.
+* in struct definitions, fields should be expandable to their type