[Harsh23Kashyap]

Fixes #7360.

When the same section header appears twice, parse replaces the first section's object with a fresh one, so every key from the earlier occurrence vanishes without an error:

parse("[s]\na=1\n[s]\nb=2");
// before: { s: { b: 2 } }   (a=1 silently gone)
// after:  { s: { a: 1, b: 2 } }

With this change a repeated section name reuses the existing section object, so the keys merge. That matches what node-ini does, and it composes with the rules parse already pins elsewhere: a key repeated across the two occurrences still resolves last-assignment-wins (same as a repeated key within one section), and a top-level key sharing the section's name is still replaced by the section.

Python's configparser raises DuplicateSectionError for this instead. Merging felt like the better fit here since parse never throws for repeated content anywhere else.

Tests added for the merge, the last-wins key case, and the top-level key collision. deno test -A ini/, deno lint ini/, and deno fmt --check ini/ all pass.

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.04%. Comparing base (f834d02) to head (60e728a).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7361      +/-   ##
==========================================
- Coverage   95.04%   95.04%   -0.01%     
==========================================
  Files         619      618       -1     
  Lines       52012    51765     -247     
  Branches     9450     9405      -45     
==========================================
- Hits        49434    49199     -235     
+ Misses       2031     2022       -9     
+ Partials      547      544       -3     

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