feat(stats/halfnormal): add PDF implementation, tests, and update README

[anujmishra03]

Resolves #{{TODO: add issue number}}.

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Related Issues

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• #{{TODO: add related issue number}}

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Coverage Report

Package	Statements	Branches	Functions	Lines
blas/base/isamax	$\color{green}369/369$ $color{green}+100.00%$	$\color{green}20/20$ $color{green}+100.00%$	$\color{green}4/4$ $color{green}+100.00%$	$\color{green}369/369$ $color{green}+100.00%$
blas/ext/sorthp	$\color{green}442/442$ $color{green}+100.00%$	$\color{green}47/47$ $color{green}+100.00%$	$\color{green}6/6$ $color{green}+100.00%$	$\color{green}442/442$ $color{green}+100.00%$
blas/ext/to-sortedhp	$\color{green}372/372$ $color{green}+100.00%$	$\color{green}33/33$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}372/372$ $color{green}+100.00%$
math/base/special/cceilf	$\color{green}165/165$ $color{green}+100.00%$	$\color{green}5/5$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}165/165$ $color{green}+100.00%$
math/base/special/factoriallnf	$\color{green}186/186$ $color{green}+100.00%$	$\color{green}7/7$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}186/186$ $color{green}+100.00%$
math/base/special/floor	$\color{green}157/157$ $color{green}+100.00%$	$\color{green}4/4$ $color{green}+100.00%$	$\color{green}1/1$ $color{green}+100.00%$	$\color{green}157/157$ $color{green}+100.00%$
math/base/special/fresnels	$\color{red}437/446$ $color{green}+97.98%$	$\color{red}22/28$ $color{green}+78.57%$	$\color{green}5/5$ $color{green}+100.00%$	$\color{red}437/446$ $color{green}+97.98%$
math/base/special/hacoversin	$\color{green}164/164$ $color{green}+100.00%$	$\color{green}5/5$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}164/164$ $color{green}+100.00%$
math/base/special/haversin	$\color{green}164/164$ $color{green}+100.00%$	$\color{green}5/5$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}164/164$ $color{green}+100.00%$
math/base/special/round	$\color{green}236/236$ $color{green}+100.00%$	$\color{green}4/4$ $color{green}+100.00%$	$\color{green}1/1$ $color{green}+100.00%$	$\color{green}236/236$ $color{green}+100.00%$
math/base/special/round2	$\color{green}218/218$ $color{green}+100.00%$	$\color{green}19/19$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}218/218$ $color{green}+100.00%$
math/base/special/secd	$\color{green}186/186$ $color{green}+100.00%$	$\color{green}5/5$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}186/186$ $color{green}+100.00%$
math/base/special/secdf	$\color{green}187/187$ $color{green}+100.00%$	$\color{green}5/5$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}187/187$ $color{green}+100.00%$
math/base/special/secf	$\color{green}181/181$ $color{green}+100.00%$	$\color{green}5/5$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}181/181$ $color{green}+100.00%$
math/base/special/sech	$\color{green}164/164$ $color{green}+100.00%$	$\color{green}5/5$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}164/164$ $color{green}+100.00%$
math/base/special/signum	$\color{green}178/178$ $color{green}+100.00%$	$\color{green}10/10$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}178/178$ $color{green}+100.00%$
math/base/special/signumf	$\color{green}178/178$ $color{green}+100.00%$	$\color{green}9/9$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}178/178$ $color{green}+100.00%$
math/base/special/versin	$\color{green}164/164$ $color{green}+100.00%$	$\color{green}5/5$ $color{green}+100.00%$	$\color{green}2/2$ $color{green}+100.00%$	$\color{green}164/164$ $color{green}+100.00%$
math/special	$\color{red}436/438$ $color{green}+99.54%$	$\color{red}6/7$ $color{green}+85.71%$	$\color{green}0/0$ $color{green}+100.00%$	$\color{red}436/438$ $color{green}+99.54%$
ndarray/base/copy	$\color{green}97/97$ $color{green}+100.00%$	$\color{green}3/3$ $color{green}+100.00%$	$\color{green}1/1$ $color{green}+100.00%$	$\color{green}97/97$ $color{green}+100.00%$
ndarray/base/count-falsy	$\color{red}5170/12246$ $color{green}+42.22%$	$\color{red}77/79$ $color{green}+97.47%$	$\color{red}4/64$ $color{green}+6.25%$	$\color{red}5170/12246$ $color{green}+42.22%$
ndarray/base/count-truthy	$\color{red}5170/12246$ $color{green}+42.22%$	$\color{red}77/79$ $color{green}+97.47%$	$\color{red}4/64$ $color{green}+6.25%$	$\color{red}5170/12246$ $color{green}+42.22%$
ndarray/base/every	$\color{red}12002/12006$ $color{green}+99.97%$	$\color{red}1463/1465$ $color{green}+99.86%$	$\color{green}64/64$ $color{green}+100.00%$	$\color{red}12002/12006$ $color{green}+99.97%$
ndarray/base/includes	$\color{red}12452/12461$ $color{green}+99.93%$	$\color{red}1421/1424$ $color{green}+99.79%$	$\color{green}64/64$ $color{green}+100.00%$	$\color{red}12452/12461$ $color{green}+99.93%$
ndarray/base/some	$\color{green}12523/12523$ $color{green}+100.00%$	$\color{green}1466/1466$ $color{green}+100.00%$	$\color{green}64/64$ $color{green}+100.00%$	$\color{green}12523/12523$ $color{green}+100.00%$
ndarray/concat	$\color{green}697/697$ $color{green}+100.00%$	$\color{green}63/63$ $color{green}+100.00%$	$\color{green}8/8$ $color{green}+100.00%$	$\color{green}697/697$ $color{green}+100.00%$
ndarray/dtype	$\color{green}109/109$ $color{green}+100.00%$	$\color{green}8/8$ $color{green}+100.00%$	$\color{green}1/1$ $color{green}+100.00%$	$\color{green}109/109$ $color{green}+100.00%$
stats/base/dists/halfnormal	$\color{green}41/41$ $color{green}+100.00%$	$\color{green}6/6$ $color{green}+100.00%$	$\color{green}1/1$ $color{green}+100.00%$	$\color{green}41/41$ $color{green}+100.00%$

The above coverage report was generated for the changes in this PR.