Clear the clippy warnings, except the two that are not cosmetic

Down from 29 warnings to 2, in the spirit of 4ab95ff.

The doc warnings were all one mistake made repeatedly: a paragraph wrapped so
that a line *began* with `- ` or `+ `, which rustdoc reads as a markdown list
marker and the following lines as unindented continuations. The prose always
meant an em-dash. Fixed by moving the dash to the end of the previous line and
re-wrapping; not one word changed, which is the point - these comments record
things confirmed against real printers and are worth more than the warning.
The genuine lists just had their continuations de-indented and stayed lists.

The code ones are `match x { V(v) => .., _ => {} }` to `if let`, and nested
`if let Some(x) = .. { if cond { .. } }` to a let-chain. None had an `else`,
so each is the same control flow written once instead of twice.

Two warnings are left deliberately, because fixing them is not cosmetic:
`AmsTray` (544 bytes against 32) and `BambuReport` (984 against 120) both have
one variant far larger than the rest. The fix clippy wants is a `Box`, which
changes how every reader of those enums is written and puts an allocation on
the push_status path that currently has none. Worth measuring before doing,
not worth doing to silence a warning.

51 tests still pass.

src/printer/bambu_commands/mod.rs

@@ -7,9 +7,10 @@
 //! continuum-schemas for continuum.v1, which is a schema we designed
 //! ourselves and that both TS and Rust genuinely need.
 //!
-//! One file per Bambu *category* (`get_version.rs` for "info", `pushall.rs`
-//! + `print.rs` for "pushing"/"print" - see below for why those are two
-//! files, not one). Copy `get_version.rs`'s shape for your next command.
+//! One file per Bambu *category* (`get_version.rs` for "info",
+//! `pushall.rs` + `print.rs` for "pushing"/"print" - see below for why
+//! those are two files, not one). Copy `get_version.rs`'s shape for your
+//! next command.
 //!
 //! Mirrors continuum-schemas' `schemas/bambulab/` JSON Schemas - same
 //! category split, same "print vs pushing" correction (see that

src/printer/bambu_commands/print.rs

@@ -207,9 +207,9 @@ pub struct AmsUnit {
     pub info: Option<String>,
 }
 
-/// A tray slot is either empty (just `id`) or loaded (the full field set)
-/// - two genuinely different shapes, not one shape with optional fields,
-/// so this is an untagged enum rather than a struct full of `Option<T>`.
+/// A tray slot is either empty (just `id`) or loaded (the full field set) -
+/// two genuinely different shapes, not one shape with optional fields, so
+/// this is an untagged enum rather than a struct full of `Option<T>`.
 /// `#[serde(deny_unknown_fields)]` on `Empty` is load-bearing: untagged
 /// enums try variants in order, and without it a *loaded* tray (which has
 /// every field `Empty` allows, plus more) would incorrectly match `Empty`

src/printer/bambu_mqtt.rs

@@ -162,14 +162,14 @@ impl PrintStatusCache {
         // the next one that did looked like it had skipped ahead. That is now
         // reported where it happens (see `handle_incoming_report`), which
         // leaves this warning meaning what it says.
-        if let (Some(last), Some(incoming_seq), false) = (self.last_sequence_id, incoming_seq, is_full_object) {
-            if incoming_seq != last.wrapping_add(1) {
-                eprintln!(
-                    "print.push_status sequence gap: expected {}, got {incoming_seq} - the in-memory \
-                     object may be missing whatever changed in between",
-                    last.wrapping_add(1)
-                );
-            }
+        if let (Some(last), Some(incoming_seq), false) = (self.last_sequence_id, incoming_seq, is_full_object)
+            && incoming_seq != last.wrapping_add(1)
+        {
+            eprintln!(
+                "print.push_status sequence gap: expected {}, got {incoming_seq} - the in-memory \
+                 object may be missing whatever changed in between",
+                last.wrapping_add(1)
+            );
         }
         if let Some(incoming_seq) = incoming_seq {
             self.last_sequence_id = Some(incoming_seq);
@@ -305,17 +305,17 @@ impl BambuMqttSession {
     /// whose `sequence_id` matches the one this call sent.
     ///
     /// This crate tried adding its own correlation field
-    /// (`continuum_correlation_id`) instead of relying on `sequence_id`,
-    /// on the understanding that extra fields survive into most replies.
-    /// Confirmed live that this doesn't hold for `get_version` specifically
-    /// - a real H2C's reply had exactly `["command", "module",
+    /// (`continuum_correlation_id`) instead of relying on `sequence_id`, on
+    /// the understanding that extra fields survive into most replies.
+    /// Confirmed live that this doesn't hold for `get_version`
+    /// specifically - a real H2C's reply had exactly `["command", "module",
     /// "sequence_id"]`, nothing extra at all, so the correlation field
     /// never came back and every `get_version` call just timed out.
     /// `sequence_id` is what's actually proven to round-trip for it
-    /// (confirmed earlier, live, on both protocol versions), so that's
-    /// what this uses. Whether a custom field survives on some *other*
-    /// command (`calibration`, say) is unverified, not confirmed false -
-    /// this was only ever checked for `get_version`.
+    /// (confirmed earlier, live, on both protocol versions), so that's what
+    /// this uses. Whether a custom field survives on some *other* command
+    /// (`calibration`, say) is unverified, not confirmed false - this was
+    /// only ever checked for `get_version`.
     ///
     /// Not for `print.push_status` - that's not a single reply, see
     /// `PrintStatusCache`. Not for a command with no reply at all either,

src/printer/mod.rs

@@ -143,11 +143,12 @@ pub trait GenericPrinter {
 }
 
 /// M106's `S` parameter is a raw 0-255 PWM value, not a percentage. Shared
-/// by anything that ultimately sends gcode (Bambu, PrusaLink, PrusaSerial)
-/// - *not* a trait default, since Klipper's hypothetical native fan API
-/// below takes a percent directly and has no use for this at all. Private,
-/// but still visible to bambu.rs/prusa.rs: Rust's module privacy reaches
-/// into child modules, not just the exact file it's defined in.
+/// by anything that ultimately sends gcode (Bambu, PrusaLink,
+/// PrusaSerial) - *not* a trait default, since Klipper's hypothetical
+/// native fan API below takes a percent directly and has no use for this at
+/// all. Private, but still visible to bambu.rs/prusa.rs: Rust's module
+/// privacy reaches into child modules, not just the exact file it's defined
+/// in.
 fn percent_to_pwm(percent: u8) -> u8 {
     ((percent.min(100) as u16 * 255) / 100) as u8
 }