feat(t-variance): fixing readme

Author: Aadish Jain

lib/node_modules/@stdlib/stats/base/dists/t/variance/README.md

@@ -166,7 +166,7 @@ double out = stdlib_base_dists_t_variance( 5.0 );
 
 The function accepts the following arguments:
 
--   **v**: `[in] double` input value.
+-   **v**: `[in] double` degrees of freedom.
 
 ```c
 double stdlib_base_dists_t_variance( const double v );