Fix srdist by passing nranges=1 to Rmath.ptukey/qtukey

[devmotion]

Summary

The inlining of the RFunctions macro in #188 dropped the special-case that
appended a literal 1 for :tukey, so the lower_tail/log_p Bool flags
shifted into the nranges positional slot of Rmath.ptukey/qtukey. As a
result, srdistcdf ↔ srdistccdf are silently inverted on v2.0.0 and the
inverse CDF functions also return wrong values. For example:

julia> using StatsFuns

julia> srdistcdf(2.0, 2.0, 0.0)         # should be 0
1.0

Restore the missing 1 argument explicitly in all 8 Rmath.ptukey/qtukey
calls.

Why the existing tests didn't catch it

The rmathcomp harness compared StatsFuns' buggy srdistcdf against an
equally buggy direct Rmath.ptukey(..., true, false) call, so the test
agreed with itself. Fix the harness to inject nranges=1 for tukey when
building the Rmath-side lambdas, and add a strict-equality
@testset "srdist boundary behaviour" covering x = 0 and x = Inf for
all four cdf-like functions.

Test plan

• Pkg.test() passes locally (full suite)
• New srdist boundary behaviour testset passes (8 strict == assertions)
• Verified Distributions.jl's StudentizedRange and
  Truncated{StudentizedRange} test failures on Update to StatsFuns@2 Distributions.jl#2062
  go away when this branch is dev'd in

🤖 Generated with Claude Code

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.39%. Comparing base (53dc188) to head (72e46fe).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #211   +/-   ##
=======================================
  Coverage   72.39%   72.39%           
=======================================
  Files          22       22           
  Lines        1007     1007           
=======================================
  Hits          729      729           
  Misses        278      278           

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