fix: correct README variance reference and convert C docs to Doxygen format

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Author: Planeshifter

lib/node_modules/@stdlib/stats/base/dists/arcsine/quantile/README.md

@@ -163,7 +163,7 @@ logEachMap( 'p: %0.4f, a: %0.4f, b: %0.4f, Q(p;a,b): %0.4f', p, a, b, quantile )
 
 #### stdlib_base_dists_arcsine_quantile( p, a, b )
 
-Returns the variance of an arcsine distribution.
+Evaluates the quantile function for an arcsine distribution.
 
 ```c
 double out = quantile( 0.8, 0.0, 1.0 );

lib/node_modules/@stdlib/stats/base/dists/arcsine/quantile/src/main.c

@@ -27,13 +27,13 @@
 /**
 * Evaluates the quantile function for an arcsine distribution with minimum support `a` and maximum support `b` at a probability `p`.
 *
-* @param {Probability} p - input value
-* @param {number} a - minimum support
-* @param {number} b - maximum support
-* @returns {number} evaluated quantile function
+* @param p    input value
+* @param a    minimum support
+* @param b    maximum support
+* @return     evaluated quantile function
 *
 * @example
-* var y = quantile( 0.8, 0.0, 1.0 );
+* double y = stdlib_base_dists_arcsine_quantile( 0.8, 0.0, 1.0 );
 * // returns ~0.905
 */
 double stdlib_base_dists_arcsine_quantile( const double p, const double a, const double b ) {