feat!: collect names for return types in parser

[ilbertt]

Overview
Named arguments can also be in the return type according to the spec. This PR updates the grammar to collect the names of the return types.

As a consequence, it fixes a regression introduced in https://github.com/dfinity/candid/pull/612/files#diff-c5ff9610c5d6538ec79f3d465965d2b3a3e3b628b16854a91b4b4a90ba766a57L220-L230, in order to keep parsing the return types with arguments without errors.

Updates a test case to check if the behavior has been restored.

[github-actions]

Name	Max Mem (Kb)	Encode	Decode
blob	4_224	4_208_077 ($\textcolor{red}{0.00\%}$)	2_120_230 ($\textcolor{red}{0.00\%}$)
btreemap	75_456	4_701_848_211 ($\textcolor{red}{0.00\%}$)	15_580_167_369 ($\textcolor{green}{-0.24\%}$)
nns	192	1_628_223 ($\textcolor{red}{1.16\%}$)	3_354_727 ($\textcolor{red}{0.21\%}$)
nns_list_proposal	1_088	6_570_615 ($\textcolor{green}{-0.09\%}$)	47_649_447 ($\textcolor{red}{0.07\%}$)
option_list	128	8_026_733 ($\textcolor{green}{-0.00\%}$)	25_896_825 ($\textcolor{green}{-0.60\%}$)
text	6_336	4_204_221	7_877_878 ($\textcolor{red}{0.00\%}$)
variant_list	128	8_021_720 ($\textcolor{red}{0.00\%}$)	24_231_303 ($\textcolor{green}{-0.32\%}$)
vec_int16	16_704	123_695_548 ($\textcolor{red}{0.00\%}$)	950_032_334 ($\textcolor{red}{0.00\%}$)

• Parser cost: 17_168_623 ($\textcolor{red}{0.09\%}$)
• Extra args: 2_522_653 ($\textcolor{red}{0.01\%}$)

Click to see raw report

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Benchmark: blob
  total:
    instructions: 6.33 M (0.00%) (change within noise threshold)
    heap_increase: 66 pages (no change)
    stable_memory_increase: 0 pages (no change)

  1. Encoding (scope):
    calls: 1 (no change)
    instructions: 4.21 M (0.00%) (change within noise threshold)
    heap_increase: 66 pages (no change)
    stable_memory_increase: 0 pages (no change)

  2. Decoding (scope):
    calls: 1 (no change)
    instructions: 2.12 M (0.00%) (change within noise threshold)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

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Benchmark: text
  total:
    instructions: 12.08 M (0.00%) (change within noise threshold)
    heap_increase: 99 pages (no change)
    stable_memory_increase: 0 pages (no change)

  1. Encoding (scope):
    calls: 1 (no change)
    instructions: 4.20 M (no change)
    heap_increase: 66 pages (no change)
    stable_memory_increase: 0 pages (no change)

  2. Decoding (scope):
    calls: 1 (no change)
    instructions: 7.88 M (0.00%) (change within noise threshold)
    heap_increase: 33 pages (no change)
    stable_memory_increase: 0 pages (no change)

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Benchmark: vec_int16
  total:
    instructions: 1.07 B (0.00%) (change within noise threshold)
    heap_increase: 261 pages (no change)
    stable_memory_increase: 0 pages (no change)

  1. Encoding (scope):
    calls: 1 (no change)
    instructions: 123.70 M (0.00%) (change within noise threshold)
    heap_increase: 261 pages (no change)
    stable_memory_increase: 0 pages (no change)

  2. Decoding (scope):
    calls: 1 (no change)
    instructions: 950.03 M (0.00%) (change within noise threshold)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

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Benchmark: btreemap
  total:
    instructions: 20.28 B (-0.18%) (change within noise threshold)
    heap_increase: 1179 pages (no change)
    stable_memory_increase: 0 pages (no change)

  1. Encoding (scope):
    calls: 1 (no change)
    instructions: 4.70 B (0.00%) (change within noise threshold)
    heap_increase: 159 pages (no change)
    stable_memory_increase: 0 pages (no change)

  2. Decoding (scope):
    calls: 1 (no change)
    instructions: 15.58 B (-0.24%) (change within noise threshold)
    heap_increase: 1020 pages (no change)
    stable_memory_increase: 0 pages (no change)

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Benchmark: option_list
  total:
    instructions: 33.93 M (-0.46%) (change within noise threshold)
    heap_increase: 2 pages (no change)
    stable_memory_increase: 0 pages (no change)

  1. Encoding (scope):
    calls: 1 (no change)
    instructions: 8.03 M (-0.00%) (change within noise threshold)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

  2. Decoding (scope):
    calls: 1 (no change)
    instructions: 25.90 M (-0.60%) (change within noise threshold)
    heap_increase: 2 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: variant_list
  total:
    instructions: 32.26 M (-0.24%) (change within noise threshold)
    heap_increase: 2 pages (no change)
    stable_memory_increase: 0 pages (no change)

  1. Encoding (scope):
    calls: 1 (no change)
    instructions: 8.02 M (0.00%) (change within noise threshold)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

  2. Decoding (scope):
    calls: 1 (no change)
    instructions: 24.23 M (-0.32%) (change within noise threshold)
    heap_increase: 2 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: nns
  total:
    instructions: 23.10 M (0.18%) (change within noise threshold)
    heap_increase: 3 pages (no change)
    stable_memory_increase: 0 pages (no change)

  0. Parsing (scope):
    calls: 1 (no change)
    instructions: 17.17 M (0.09%) (change within noise threshold)
    heap_increase: 3 pages (no change)
    stable_memory_increase: 0 pages (no change)

  1. Encoding (scope):
    calls: 1 (no change)
    instructions: 1.63 M (1.16%) (change within noise threshold)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

  2. Decoding (scope):
    calls: 1 (no change)
    instructions: 3.35 M (0.21%) (change within noise threshold)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: nns_list_proposal
  total:
    instructions: 54.22 M (0.05%) (change within noise threshold)
    heap_increase: 17 pages (no change)
    stable_memory_increase: 0 pages (no change)

  1. Encoding (scope):
    calls: 1 (no change)
    instructions: 6.57 M (-0.09%) (change within noise threshold)
    heap_increase: 3 pages (no change)
    stable_memory_increase: 0 pages (no change)

  2. Decoding (scope):
    calls: 1 (no change)
    instructions: 47.65 M (0.07%) (change within noise threshold)
    heap_increase: 14 pages (no change)
    stable_memory_increase: 0 pages (no change)

---------------------------------------------------

Benchmark: extra_args
  total:
    instructions: 2.52 M (0.01%) (change within noise threshold)
    heap_increase: 0 pages (no change)
    stable_memory_increase: 0 pages (no change)

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Summary:
  instructions:
    status:   No significant changes 👍
    counts:   [total 9 | regressed 0 | improved 0 | new 0 | unchanged 9]
    change:   [max +40.39K | p75 +246 | median +153 | p25 -77.61K | min -36.70M]
    change %: [max +0.18% | p75 0.01% | median 0.00% | p25 -0.18% | min -0.46%]

  heap_increase:
    status:   No significant changes 👍
    counts:   [total 9 | regressed 0 | improved 0 | new 0 | unchanged 9]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

  stable_memory_increase:
    status:   No significant changes 👍
    counts:   [total 9 | regressed 0 | improved 0 | new 0 | unchanged 9]
    change:   [max 0 | p75 0 | median 0 | p25 0 | min 0]
    change %: [max 0.00% | p75 0.00% | median 0.00% | p25 0.00% | min 0.00%]

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Successfully persisted results to canbench_results.yml