docs: update return annotation per conventions

Signed-off-by: Philipp Burckhardt <[email protected]>

Author: Planeshifter

lib/node_modules/@stdlib/stats/base/dists/degenerate/logpmf/README.md

@@ -129,7 +129,7 @@ Evaluate the natural logarithm of the [probability mass function][pmf] (PMF) for
 
 ```c
 double out = stdlib_base_dists_degenerate_logpmf( 2.0, 3.0 );
-// returns -INFINITY
+// returns -Infinity
 ```
 
 The function accepts the following arguments: