Add missing PathLink in JSON-Cadence Data Interchange Format Specs

[fxamacker]

Description

The JSON-Cadence Data Interchange Format specification is missing PathLink.

This PR adds PathLink to the specs.

---

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[codecov]

Codecov Report

Merging #2208 (16a685f) into master (79b7013) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2208   +/-   ##
=======================================
  Coverage   77.69%   77.69%           
=======================================
  Files         309      309           
  Lines       65682    65682           
=======================================
  Hits        51030    51030           
  Misses      12875    12875           
  Partials     1777     1777           

Flag	Coverage Δ
unittests	77.69% <ø> (ø)

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[github-actions]

Cadence Benchstat comparison

This branch with compared with the base branch onflow:master commit 79b7013
The command for i in {1..N}; do go test ./... -run=XXX -bench=. -benchmem -shuffle=on; done was used.
Bench tests were run a total of 7 times on each branch.

Collapsed results for better readability

	old.txt	new.txt
	time/op		delta
CheckContractInterfaceFungibleTokenConformance-2	111µs ±11%	107µs ± 0%	~	(p=0.073 n=7+6)
ContractInterfaceFungibleToken-2	37.1µs ± 1%	37.0µs ± 1%	~	(p=1.000 n=7+7)
InterpretRecursionFib-2	2.49ms ± 0%	2.48ms ± 0%	~	(p=0.295 n=7+6)
NewInterpreter/new_interpreter-2	1.07µs ± 1%	1.15µs ±12%	~	(p=0.126 n=7+7)
NewInterpreter/new_sub-interpreter-2	587ns ± 6%	592ns ± 6%	~	(p=0.456 n=7+7)
ParseArray-2	7.49ms ± 1%	7.70ms ± 9%	~	(p=0.259 n=7+7)
ParseDeploy/byte_array-2	11.5ms ± 3%	11.3ms ± 2%	~	(p=0.234 n=7+6)
ParseDeploy/decode_hex-2	1.21ms ± 7%	1.19ms ± 0%	~	(p=0.902 n=7+7)
ParseFungibleToken/With_memory_metering-2	183µs ± 6%	182µs ± 5%	~	(p=0.620 n=7+7)
ParseFungibleToken/Without_memory_metering-2	141µs ± 0%	141µs ± 1%	~	(p=0.240 n=6+6)
ParseInfix-2	7.06µs ± 1%	7.05µs ± 1%	~	(p=0.386 n=7+6)
QualifiedIdentifierCreation/One_level-2	2.58ns ±12%	2.42ns ± 1%	~	(p=0.169 n=7+6)
QualifiedIdentifierCreation/Three_levels-2	116ns ± 0%	120ns ± 8%	~	(p=0.133 n=6+7)
RuntimeFungibleTokenTransfer-2	421µs ± 0%	533µs ±23%	~	(p=0.343 n=5+7)
RuntimeResourceDictionaryValues-2	5.07ms ± 1%	5.06ms ± 1%	~	(p=0.805 n=7+7)
RuntimeScriptNoop-2	15.4µs ±39%	13.1µs ± 1%	~	(p=0.731 n=7+6)
SuperTypeInference/arrays-2	290ns ± 5%	287ns ± 1%	~	(p=0.704 n=7+6)
SuperTypeInference/composites-2	129ns ± 0%	129ns ± 0%	~	(p=0.219 n=7+6)
SuperTypeInference/integers-2	92.2ns ± 0%	92.2ns ± 0%	~	(p=0.828 n=7+7)
ValueIsSubtypeOfSemaType-2	86.0ns ± 3%	89.2ns ±10%	~	(p=0.295 n=6+7)
	alloc/op		delta
CheckContractInterfaceFungibleTokenConformance-2	48.6kB ± 0%	48.6kB ± 0%	~	(all equal)
ContractInterfaceFungibleToken-2	22.8kB ± 0%	22.8kB ± 0%	~	(all equal)
InterpretRecursionFib-2	1.00MB ± 0%	1.00MB ± 0%	~	(all equal)
NewInterpreter/new_interpreter-2	768B ± 0%	768B ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-2	200B ± 0%	200B ± 0%	~	(all equal)
ParseArray-2	2.70MB ± 6%	2.73MB ± 3%	~	(p=0.318 n=7+7)
ParseDeploy/byte_array-2	4.21MB ± 3%	4.18MB ± 2%	~	(p=0.710 n=7+7)
ParseDeploy/decode_hex-2	214kB ± 0%	214kB ± 0%	~	(p=0.131 n=7+7)
ParseFungibleToken/With_memory_metering-2	29.2kB ± 0%	29.2kB ± 0%	~	(p=0.080 n=7+6)
ParseFungibleToken/Without_memory_metering-2	29.2kB ± 0%	29.2kB ± 0%	~	(p=0.883 n=7+7)
ParseInfix-2	1.92kB ± 0%	1.92kB ± 0%	~	(p=0.601 n=7+7)
QualifiedIdentifierCreation/One_level-2	0.00B	0.00B	~	(all equal)
QualifiedIdentifierCreation/Three_levels-2	64.0B ± 0%	64.0B ± 0%	~	(all equal)
RuntimeFungibleTokenTransfer-2	101kB ± 0%	101kB ± 1%	~	(p=0.168 n=6+7)
RuntimeResourceDictionaryValues-2	2.28MB ± 0%	2.28MB ± 0%	~	(p=0.535 n=7+7)
RuntimeScriptNoop-2	6.76kB ± 0%	6.76kB ± 0%	~	(p=0.688 n=7+7)
SuperTypeInference/arrays-2	96.0B ± 0%	96.0B ± 0%	~	(all equal)
SuperTypeInference/composites-2	0.00B	0.00B	~	(all equal)
SuperTypeInference/integers-2	0.00B	0.00B	~	(all equal)
ValueIsSubtypeOfSemaType-2	48.0B ± 0%	48.0B ± 0%	~	(all equal)
	allocs/op		delta
CheckContractInterfaceFungibleTokenConformance-2	794 ± 0%	794 ± 0%	~	(all equal)
ContractInterfaceFungibleToken-2	363 ± 0%	363 ± 0%	~	(all equal)
InterpretRecursionFib-2	18.9k ± 0%	18.9k ± 0%	~	(all equal)
NewInterpreter/new_interpreter-2	13.0 ± 0%	13.0 ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-2	4.00 ± 0%	4.00 ± 0%	~	(all equal)
ParseArray-2	59.6k ± 0%	59.6k ± 0%	~	(p=0.592 n=7+7)
ParseDeploy/byte_array-2	89.4k ± 0%	89.4k ± 0%	~	(p=0.592 n=7+7)
ParseDeploy/decode_hex-2	64.0 ± 0%	64.0 ± 0%	~	(all equal)
ParseFungibleToken/With_memory_metering-2	779 ± 0%	779 ± 0%	~	(all equal)
ParseFungibleToken/Without_memory_metering-2	779 ± 0%	779 ± 0%	~	(all equal)
ParseInfix-2	48.0 ± 0%	48.0 ± 0%	~	(all equal)
QualifiedIdentifierCreation/One_level-2	0.00	0.00	~	(all equal)
QualifiedIdentifierCreation/Three_levels-2	2.00 ± 0%	2.00 ± 0%	~	(all equal)
RuntimeFungibleTokenTransfer-2	1.96k ± 0%	1.96k ± 0%	−0.03%	(p=0.042 n=6+7)
RuntimeResourceDictionaryValues-2	36.9k ± 0%	36.9k ± 0%	~	(p=1.000 n=7+7)
RuntimeScriptNoop-2	98.0 ± 0%	98.0 ± 0%	~	(all equal)
SuperTypeInference/arrays-2	3.00 ± 0%	3.00 ± 0%	~	(all equal)
SuperTypeInference/composites-2	0.00	0.00	~	(all equal)
SuperTypeInference/integers-2	0.00	0.00	~	(all equal)
ValueIsSubtypeOfSemaType-2	1.00 ± 0%	1.00 ± 0%	~	(all equal)

[turbolent]

I think we might not need this, see #2167 (comment)