src,test: Fix readability-implicit-bool-conversion warnings

[stotko]

limits exploits the fact that boolean values may implicitly be converted to 1 and 0 integer values. This is useful for computing the number of digits for types that may be signed or unsigned such as char and wchar_t. Fix the related clang-tidy warnings by explicitly casting the boolean values to integers making this intentional usage clear.

[codecov]

Codecov Report

Merging #134 into master will increase coverage by 0.11%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #134      +/-   ##
==========================================
+ Coverage   97.57%   97.69%   +0.11%     
==========================================
  Files          28       28              
  Lines        1694     1694              
==========================================
+ Hits         1653     1655       +2     
+ Misses         41       39       -2     

Impacted Files	Coverage Δ
src/stdgpu/impl/limits_detail.h	100.00% <ø> (ø)
src/stdgpu/impl/unordered_base_detail.cuh	96.74% <0.00%> (+0.50%)	⬆️

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