Fix duplicated words in documentation comments

[geographybuff]

Rationale for this change

Several comments contain accidentally doubled words — strike rate for the the call option, with digital digital call/put option, see if if ok. Six of the eight are Doxygen //! comments on public classes and data members, so they render in the generated reference documentation.

These survive automated checking. The misspell-fixer workflow runs on every push and auto-opens correction PRs (e.g. #796), but it matches misspelled words; a correctly spelled word repeated twice is not a misspelling, so it cannot detect these. Running misspell-fixer locally over the six files below reports nothing, while a control file containing recieve and seperate is flagged immediately.

Found by searching the tree for \b(\w+)\s+\1\b restricted to comment lines.

What changes are included in this PR?

Removes 8 doubled words across 6 files. Comment text only — no code changes.

File	Fix
ql/cashflows/digitalcoupon.hpp (x2)	strike rate for the the call option / for the the put option, on the callStrike_ and putStrike_ members
ql/cashflows/digitaliborcoupon.hpp	Ibor rate coupon with digital digital call/put option
ql/cashflows/digitalcmscoupon.hpp	Cms-rate coupon with digital digital call/put option
ql/experimental/coupons/digitalcmsspreadcoupon.hpp	Cms-spread-rate coupon with digital digital call/put option
ql/experimental/inflation/yoycapfloortermpricesurface.hpp	Heuristic: overwrite the the swap rate
ql/models/marketmodels/models/alphafinder.cpp (x2)	see if if ok at some intermediate point

Deliberately left alone, as these are not typos:

• float float swap in ql/instruments/floatfloatswap.hpp and ql/pricingengines/swaption/gaussian1dfloatfloatswaptionengine.hpp — this names the FloatFloatSwap instrument.
• barrier barrier type in test-suite/barrieroption.cpp — column headings in a data table.
• rank inf/inf 5/inf inf/5 5/5 in test-suite/nthtodefault.cpp.

Testing

No new tests. The change is confined to comments, so there is no behaviour to cover.

Checks run locally on Linux x86_64, g++ 13.3.0, Boost 1.83, C++17:

• ./tools/check_all_header_docs.sh (the header-docs job in .github/workflows/doxygen.yml) — pass
• Syntax-only compile of a translation unit including all five changed headers, g++ -std=c++17 -fsyntax-only against a CMake-generated ql/config.hpp — pass
• Full compile of the one changed source file, g++ -std=c++17 -c -O2 -Wall ql/models/marketmodels/models/alphafinder.cpp — pass, no warnings

I could not run make docs. It fails on my machine with Docs/quantlibheader.html: error: Remaining begin replacement with marker 'HTML_DYNAMIC_SECTIONS', and it fails identically on an unmodified checkout of master, so this is a local Doxygen version mismatch (1.9.8 from Ubuntu, against the newer Homebrew Doxygen the macOS CI job uses) and not an effect of this PR. The Doxygen job on this PR will be the first real run of that check.

I also did not run the full test-suite; no changed line is code.

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AI disclosure

This contribution was AI-assisted. Claude Code (Claude Opus 5) performed the tree-wide doubled-word search, made the 8 line edits, and ran the checks listed above. The check commands were executed by the AI and have not been independently re-run by hand.

[boring-cyborg]

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[boring-cyborg]

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