Import type names instead of writing their paths (#355)

The style guide imports types and uses them unqualified. 222 places
wrote a path such as std::collections::HashMap or std::time::Duration
inline; each file now imports the type once, one use a module, and
names it bare. Done with a script, file by file, only where the name is
unambiguous there:
- one path for the name throughout the file, and not a name the file
  already binds otherwise (its own types, other imports, a function's
  local use);
- not a name generic enough to mislead bare (Error, Result, Value,
  Mutex, Client, Request, Response, Command, Event, Context, Map, Ok);
- only code a normal build compiles, so no import is unused outside
  tests or names a crate only tests depend on.

193 paths stay, those cases above. No behaviour change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/directory/src/site.rs

@@ -16,6 +16,7 @@ use axum::response::{IntoResponse, Response};
 use axum::routing::get;
 
 use crate::{Listing, Shared};
+use url::form_urlencoded::Serializer;
 
 pub fn router() -> Router<Shared> {
     Router::new()
@@ -140,7 +141,7 @@ async fn listed(dir: &Shared, title: &str, here: &str, f: &Filter, pick: impl Fn
 
     // The query a link keeps, with one of its keys changed.
     let link = |kind: Option<&str>, sub: Option<&str>| {
-        let mut q = url::form_urlencoded::Serializer::new(String::new());
+        let mut q = Serializer::new(String::new());
         if let Some(v) = f.q.as_deref() {
             q.append_pair("q", v);
         }