[perf-only] rustdoc: Unconditionally enable --generate-link-to-definition

[fmease]

Compare with #156355, #156349.

[fmease]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 68c2bff (68c2bff6cb08a87e59246064a6a9f37098e22c3f, parent: fb0a5a5a9c892b351f34263d6d84da9dde72871a)

[rust-timer]

Finished benchmarking commit (68c2bff): comparison URL.

Overall result: ❌ regressions - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	16.5%	[2.1%, 44.1%]	19
Regressions ❌ (secondary)	13.2%	[0.3%, 120.7%]	19
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	16.5%	[2.1%, 44.1%]	19

Max RSS (memory usage)

Results (primary 5.0%, secondary 4.6%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	5.5%	[1.3%, 14.9%]	16
Regressions ❌ (secondary)	4.6%	[1.4%, 8.8%]	6
Improvements ✅ (primary)	-2.1%	[-2.1%, -2.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	5.0%	[-2.1%, 14.9%]	17

Cycles

Results (primary 21.0%, secondary 17.7%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	21.0%	[2.4%, 56.4%]	19
Regressions ❌ (secondary)	17.7%	[2.2%, 101.4%]	15
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	21.0%	[2.4%, 56.4%]	19

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 497.93s -> 497.245s (-0.14%)
Artifact size: 397.14 MiB -> 397.10 MiB (-0.01%)