librustdoc: more usages of Joined::joined

[yotamofek]

Some missed opportunities from #136244
r? @GuillaumeGomez since you reviewed the last one (feel free to re-assign, of course 😊)
First two commits are just drive-by cleanups

[yotamofek]

looked a little deeper at this and turned out neither myitem.type_() or full_path(...) can ever be empty, so the whole joined-array thing is unneeded

[yotamofek]

The logic here is weird (pre-existing).
The kw::PathRoot should only ever be the first segment, I think. And we wouldn't want to join two "::"s together anyways.

[GuillaumeGomez]

Wow, you're on fire. :D

Let's check perf results then!

@bors try @rust-timer queue

[bors]

⌛ Trying commit 2341962 with merge 2ffed9b...

[bors]

☀️ Try build successful - checks-actions
Build commit: 2ffed9b (2ffed9b0223e35c5c90123aee8a6868058ebb856)

[yotamofek]

@GuillaumeGomez I think the perf bot didn't work?

[GuillaumeGomez]

Ah indeed. Let's try again.

@rust-timer queue

[GuillaumeGomez]

Still not apparently. Fun times.

@rust-timer build 2ffed9b

[rust-timer]

Finished benchmarking commit (2ffed9b): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results (primary -0.2%, secondary 2.1%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	1.6%	[1.6%, 1.6%]	1
Regressions ❌ (secondary)	2.1%	[2.1%, 2.1%]	1
Improvements ✅ (primary)	-2.1%	[-2.1%, -2.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.2%	[-2.1%, 1.6%]	2

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 778.801s -> 776.752s (-0.26%)
Artifact size: 328.78 MiB -> 328.82 MiB (0.01%)