Implement ExplicitCollectionElementAccessMethod rule

[smyachenkov]

This PR adds new rule ExplicitCollectionElementAccessMethod to style ruleset.

Rule ExplicitCollectionElementAccessMethod reports usage of get or put methods and suggests to use Indexed access operator: []. This rule can be applied to Kotlin collections which implement Map or List interfaces as well as Java collections java.util.AbstractMap and java.util.AbstractList.

Noncompliant Code:

val map = mapOf<String, String>() 
val list = listOf<String>() 

map.put("key", "val") 
map.get("key") 
list.get(0) 

Compliant Code:

val map = mapOf<String, String>() 
map["key"] = "val" 
map["key"] 
list[0] 

This is a rule for Style ruleset. It is implemented to introduce users to indexed access operator and help them write shorter and more idiomatic code.

[schalkms]

Please rebase since #2217 was closed.

[codecov-io]

Codecov Report

Merging #2215 into master will decrease coverage by 0.1%.
The diff coverage is 78.78%.

@@             Coverage Diff              @@
##             master    #2215      +/-   ##
============================================
- Coverage     81.35%   81.24%   -0.11%     
- Complexity     2067     2111      +44     
============================================
  Files           341      349       +8     
  Lines          5968     6053      +85     
  Branches       1086     1106      +20     
============================================
+ Hits           4855     4918      +63     
- Misses          532      535       +3     
- Partials        581      600      +19

Impacted Files	Coverage Δ	Complexity Δ
...bosch/detekt/rules/providers/StyleGuideProvider.kt	100% <100%> (ø)	3 <0> (ø)	⬇️
...les/style/ExplicitCollectionElementAccessMethod.kt	78.12% <78.12%> (ø)	10 <10> (?)
.../gitlab/arturbosch/detekt/rules/MethodSignature.kt	50% <0%> (-10%)	0% <0%> (ø)
...ab/arturbosch/detekt/cli/console/FindingsReport.kt	88% <0%> (-6.12%)	7% <0%> (ø)
...in/kotlin/io/gitlab/arturbosch/detekt/api/Issue.kt	85.71% <0%> (-3.76%)	5% <0%> (ø)
...osch/detekt/cli/console/FileBasedFindingsReport.kt	89.28% <0%> (-3.31%)	7% <0%> (-1%)
...bosch/detekt/rules/complexity/MethodOverloading.kt	91.17% <0%> (-2.16%)	5% <0%> (ø)
...turbosch/detekt/rules/style/UnusedPrivateMember.kt	93.47% <0%> (ø)	5% <0%> (ø)	⬇️
...osch/detekt/rules/bugs/WrongEqualsTypeParameter.kt	100% <0%> (ø)	10% <0%> (+3%)	⬆️
...ch/detekt/formatting/wrappers/EnumEntryNameCase.kt	100% <0%> (ø)	2% <0%> (?)
... and 14 more

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[schalkms]

Thanks for implementing this rule. First time Kotlin users will certainly benefit from this rule! 👍
Can we please make sure that the implementation is thoroughly tested? Codecov does report some misses for the rule implementation. After that, the build is completely green and I'll merge this!
Please see my other minor comments about the implementation.

[schalkms]

Please try to work around this @Suppress by merging the first two if's for example.

[smyachenkov]

I've refactored this class to avoid usage of @Suppress, please check it one more time

[schalkms]

Thanks that looks good!