Style/StringHashKeys is not safe for autocorrection

[fig]

I don't believe that Style/StringHashKeys should be labeled as safe for autocorrection.

As an example, a Hash may be passed as the second argument to String#gsub. If the matched text is one of its keys, the corresponding value is the replacement string. Converting the String key to a Symbol will break the replacement.

---

Steps to reproduce the problem

example scenario:

"The sky is green.".gsub(/green/, "green" => "blue")
# => "The sky is blue."

after auto correct:

"The sky is green.".gsub(/green/, green: "blue")
# => "The sky is ."

RuboCop version

$ rubocop -V
0.67.2 (using Parser 2.6.2.1, running on ruby 2.6.3 x86_64-linux)

---

A solution might be to ignore StringHashKeys if they occur as an argument to #gsub / #gsub!

[tejasbubane]

There are existing exceptions in Style/StringHashKeys for IO.popen, etc. So I added gsub and gsub! to the list.