Refresh rdoc within existing constraints

Update the lockfile to rdoc 7.2.0 as a conservative dependency refresh
without changing gemspec constraints, and record the update in CHANGELOG.

Author: evolve75

CHANGELOG.md

@@ -40,6 +40,9 @@ Changes section to scan for breaking or behavioral changes.
   `[key, value]`, `{ key:, value: }`, and `Entry` inputs.
 * Clarify in docs that `Tree::FenwickTree` and `Tree::SegmentTree` do not
   support `<<`, and add tests asserting that unsupported behavior.
+* Refresh development dependencies with a conservative lockfile update by
+  upgrading `rdoc` from `7.1.0` to `7.2.0` within existing version
+  constraints.
 
 ### 3.0.0pre / 2026-02-09
 

Gemfile.lock

@@ -52,7 +52,7 @@ GEM
     racc (1.8.1)
     rainbow (3.1.1)
     rake (13.3.1)
-    rdoc (7.1.0)
+    rdoc (7.2.0)
       erb
       psych (>= 4.0.0)
       tsort