Update dependency rdoc to v6.14.1

Author: renovate[bot]

Gemfile.lock

@@ -38,6 +38,7 @@ GEM
     date (3.4.1)
     diff-lcs (1.6.2)
     docile (1.4.1)
+    erb (5.0.1)
     ffi (1.17.2-arm64-darwin)
     ffi (1.17.2-x64-mingw-ucrt)
     ffi (1.17.2-x86_64-linux-gnu)
@@ -58,7 +59,8 @@ GEM
     racc (1.8.1)
     rainbow (3.1.1)
     rake (13.2.1)
-    rdoc (6.13.1)
+    rdoc (6.14.1)
+      erb
       psych (>= 4.0.0)
     regexp_parser (2.10.0)
     rubocop (1.75.5)