TwoSampleMR 0.7.5

• Amend https://gwas.mrcieu.ac.uk URLs to https://opengwas.io/
• Bump version of roxygen2 to 8.0.0 and regenerate documentation
• Replace array(1:nexp) placeholder allocations with numeric(nexp)/integer(nexp) in multivariable MR functions
• Replace 1:n with seq_len(n) in loop indices across singlesnp, leaveoneout, rucker, mr_mode, and multivariable_mr for empty-vector safety
• Pre-generate jackknife resample indices in mr_rucker_jackknife_internal and switch to lapply, matching the bootstrap function pattern
• Vectorise get_population_allele_frequency by inlining the quadratic-root logic from contingency() and picking the valid root with vectorised constraint checks
• Skip mr_wald_ratio inside mr() when more than one SNP is provided and other methods are also requested, suppressing the multi-SNP warning for default method runs while preserving the warning when mr_wald_ratio is requested on its own