Add explanation to rbs_skip_tests (#7525)

gems/bundled_gems

@@ -17,6 +17,6 @@ net-pop         0.1.2   https://github.com/ruby/net-pop
 net-smtp        0.3.3   https://github.com/ruby/net-smtp
 matrix          0.4.2   https://github.com/ruby/matrix
 prime           0.1.2   https://github.com/ruby/prime
-rbs             3.0.4   https://github.com/ruby/rbs 55f8f7d088fa71ced2154be1e28eb0e8af897528
+rbs             3.0.4   https://github.com/ruby/rbs 0dd11d38c11f55ead0a0d78bb9b19d2eaf3a2104
 typeprof        0.21.7  https://github.com/ruby/typeprof
 debug           1.7.1   https://github.com/ruby/debug 65197361213529fb5f0b5f6ec111b4d2688a3887

tool/rbs_skip_tests

@@ -1,7 +1,25 @@
+# Running tests of RBS gem may fail because of various reasons.
+# You can skip tests of RBS gem using this file, instead of pushing a new commit to `ruby/rbs` repository.
+#
+# The most frequently seen reason is the incompatibilities introduced to the unreleased version, including
+#
+# * Strict argument type check is introduced
+# * A required method parameter is added
+# * A method/class is removed
+#
+# Feel free to skip the tests with this file for that case.
+#
+# Syntax:
+#
+#   $(test-case-name) ` ` $(optional comment)    # Skipping single test case
+#   $(test-class-name) ` ` $(optional comment)   # Skipping a test class
+#
+
+test_replicate(EncodingTest) the method was removed in 3.3
+
 test_collection_install(RBS::CliTest) running tests without Bundler
 test_collection_install_frozen(RBS::CliTest) running tests without Bundler
 test_collection_update(RBS::CliTest) running tests without Bundler
-test_replicate(EncodingTest) the method was removed in 3.3
 
 NetSingletonTest depending on external resources
 NetInstanceTest depending on external resources