Update distribution.py

Updated the docstrings for better clarity. Replaced "log-likelihood" with "distribution" to accurately describe the functionality, as the class provides more than just log-likelihood including log-cdf, log-pdf.

Author: tanishy7777

pymc/distributions/distribution.py

@@ -668,7 +668,7 @@ def rv_op(cls, c, *, size=None, rng=None):
 
 class DiracDelta(Discrete):
     r"""
-    DiracDelta log-likelihood.
+    DiracDelta distribution.
 
     Parameters
     ----------