[Fix #500] Mark Performance/MapCompact cop as unsafe

Author: jbpextra

changelog/fix_mark_performance_map_compact_cop_as.md

@@ -0,0 +1 @@
+* [#500](https://github.com/rubocop/rubocop-performance/issues/500): Mark `Performance/MapCompact` cop as unsafe. ([@jbpextra][])

config/default.yml

@@ -194,7 +194,7 @@ Performance/IoReadlines:
 Performance/MapCompact:
   Description: 'Use `filter_map` instead of `collection.map(&:do_something).compact`.'
   Enabled: pending
-  SafeAutoCorrect: false
+  Safe: false
   VersionAdded: '1.11'
 
 Performance/MapMethodChain:

lib/rubocop/cop/performance/map_compact.rb

@@ -8,7 +8,7 @@ module Performance
       # This cop identifies places where `map { ... }.compact` can be replaced by `filter_map`.
       #
       # @safety
-      #   This cop's autocorrection is unsafe because `map { ... }.compact` might yield
+      #   This cop is unsafe because `map { ... }.compact` might yield
       #   different results than `filter_map`. As illustrated in the example, `filter_map`
       #   also filters out falsy values, while `compact` only gets rid of `nil`.
       #