Enable rubocop rules this project is compliant with (#537)

**What**

Enable rubocop rules this project is compliant with

- `Bundler/OrderedGems`
- `Style/CollectionMethods`
- `Style/FormatString`
- `Naming/FileName`
- `Style/SingleLineBlockParams`
- `Style/TrivialAccessors`

**Why**

Since we are compliant with these rules it feels a bit weird to have them disabled in the
`rubocop.yml` as we either are following the expectations intentionally and thus probably good to
lock down, or the lints aren't ones that are relevant to this project if they have no
issues a decade in.

.rubocop.yml

@@ -11,16 +11,10 @@ AllCops:
 Lint/AssignmentInCondition:
   Enabled: false
 
-Bundler/OrderedGems:
-  Enabled: false
-
 # Enforcing this results in a lot of unnecessary indentation.
 Style/ClassAndModuleChildren:
   Enabled: false
 
-Style/CollectionMethods:
-  Enabled: false
-
 Style/Documentation:
   Exclude:
     - 'spec/**/*'
@@ -29,16 +23,6 @@ Style/Documentation:
 Layout/DotPosition:
   EnforcedStyle: leading
 
-Style/FormatString:
-  Enabled: false
-
-Naming/FileName:
-  Exclude:
-    - 'bin/haml-lint'
-    - 'Gemfile'
-    - 'Rakefile'
-    - '*.gemspec'
-
 Style/GuardClause:
   Enabled: false
 
@@ -107,11 +91,6 @@ Naming/PredicateName:
 Style/SignalException:
   Enabled: false
 
-# Forcing a particular name (e.g. |a, e|) for inject methods prevents you from
-# choosing intention-revealing names.
-Style/SingleLineBlockParams:
-  Enabled: false
-
 Style/SpecialGlobalVars:
   Enabled: false
 
@@ -139,8 +118,5 @@ Style/TrailingCommaInArrayLiteral:
 Style/TrailingCommaInHashLiteral:
   Enabled: false
 
-Style/TrivialAccessors:
-  Enabled: false
-
 Lint/Void:
   Enabled: false