[Fix #6755] Prevent Style/TrailingCommaInArgument from breaking when a safe method call is chained on the offending method

This cop would error out on code like:

```
foo.bar(
  baz: 1,
)&.fetch(:qux)
```

This was happening because the cop wasn't taking `csend` (safe navigation)
node types into consideration.

Author: Drenmi

CHANGELOG.md

@@ -12,6 +12,7 @@
 * [#6763](https://github.com/rubocop-hq/rubocop/pull/6763): Fix false positives in range literals for `Style/MethodCallWithArgsParentheses` `omit_parentheses`. ([@gsamokovarov][])
 * [#6748](https://github.com/rubocop-hq/rubocop/issues/6748): Fix `Style/RaiseArgs` auto-correction breaking in contexts that require parentheses. ([@drenmi][])
 * [#6751](https://github.com/rubocop-hq/rubocop/issues/6751): Prevent `Style/OneLineConditional` from breaking on `retry` and `break` keywords. ([@drenmi][])
+* [#6755](https://github.com/rubocop-hq/rubocop/issues/6755): Prevent `Style/TrailingCommaInArgument` from breaking when a safe method call is chained on the offending method. ([@drenmi][], [@hoshinotsuyoshi][])
 
 ### Changes
 

lib/rubocop/cop/mixin/trailing_comma.rb

@@ -91,7 +91,7 @@ def multiline?(node)
       end
 
       def method_name_and_arguments_on_same_line?(node)
-        node.send_type? &&
+        %i[send csend].include?(node.type) &&
           node.loc.selector.line == node.arguments.last.last_line &&
           node.last_line == node.arguments.last.last_line
       end
@@ -104,7 +104,7 @@ def allowed_multiline_argument?(node)
       end
 
       def elements(node)
-        return node.children unless node.send_type?
+        return node.children unless %i[csend send].include?(node.type)
 
         node.arguments.flat_map do |argument|
           # For each argument, if it is a multi-line hash without braces,

spec/rubocop/cop/style/trailing_comma_in_arguments_spec.rb

@@ -416,6 +416,31 @@
           )
         RUBY
       end
+
+      it 'does not break when a method call is chaned on the offending one' do
+        expect_no_offenses(<<-RUBY.strip_indent)
+          foo.bar(
+            baz: 1,
+          ).fetch(:qux)
+        RUBY
+      end
+
+      it 'does not break when a safe method call is chained on the ' \
+         'offending one', :ruby23 do
+        expect_no_offenses(<<-RUBY.strip_indent)
+          foo
+            &.do_something(:bar, :baz)
+        RUBY
+      end
+
+      it 'does not break when a safe method call is chained on the ' \
+         'offending one', :ruby23 do
+        expect_no_offenses(<<-RUBY.strip_indent)
+          foo.bar(
+            baz: 1,
+          )&.fetch(:qux)
+        RUBY
+      end
     end
 
     context 'when EnforcedStyleForMultiline is consistent_comma' do