Bump minimum Ruby to 3.2, add rbs dependency, update CI

RBS 4.0 requires Ruby >= 3.2. Bump RDoc's own minimum to match and
add `rbs >= 4.0.0` as a gemspec dependency. Bump prism minimum to
`>= 1.6.0` (required by rbs). Drop JRuby and TruffleRuby from CI
matrix (rbs has a C extension that cannot build on them).

Author: st0012

.github/workflows/test.yml

@@ -14,9 +14,9 @@ jobs:
   ruby-versions:
     uses: ruby/actions/.github/workflows/ruby_versions.yml@master
     with:
-      # 2.7 breaks `test_parse_statements_nodoc_identifier_alias_method`
-      min_version: 3.0
+      min_version: 3.2
       versions: '["mswin"]'
+      engine: cruby
 
   test:
     needs: ruby-versions
@@ -26,14 +26,6 @@ jobs:
         ruby: ${{ fromJson(needs.ruby-versions.outputs.versions) }}
         os: [ubuntu-latest, macos-latest, windows-latest]
         exclude:
-          - os: windows-latest
-            ruby: truffleruby
-          - os: windows-latest
-            ruby: truffleruby-head
-          - os: windows-latest
-            ruby: jruby
-          - os: windows-latest
-            ruby: jruby-head
           - os: macos-latest
             ruby: mswin
           - os: ubuntu-latest
@@ -68,7 +60,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        prism_version: ['1.0.0', '1.3.0', '1.7.0', 'head']
+        prism_version: ['1.6.0', '1.7.0', 'head']
     runs-on: ubuntu-latest
     env:
       RUBYOPT: --enable-frozen_string_literal

Gemfile

@@ -18,7 +18,5 @@ elsif ENV['PRISM_VERSION']
 end
 
 platforms :ruby do
-  if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('3.2')
-    gem 'mini_racer' # For testing the searcher.js file
-  end
+  gem 'mini_racer' # For testing the searcher.js file
 end

rdoc.gemspec

@@ -63,11 +63,12 @@ RDoc includes the +rdoc+ and +ri+ tools for generating and displaying documentat
   s.rdoc_options = ["--main", "README.md"]
   s.extra_rdoc_files += s.files.grep(%r[\A[^\/]+\.(?:rdoc|md)\z])
 
-  s.required_ruby_version = Gem::Requirement.new(">= 2.7.0")
+  s.required_ruby_version = Gem::Requirement.new(">= 3.2.0")
   s.required_rubygems_version = Gem::Requirement.new(">= 2.2")
 
   s.add_dependency 'psych', '>= 4.0.0'
   s.add_dependency 'erb'
   s.add_dependency 'tsort'
-  s.add_dependency 'prism', '>= 1.0.0'
+  s.add_dependency 'prism', '>= 1.6.0'
+  s.add_dependency 'rbs', '>= 4.0.0'
 end