Add module-level docstrings and helper utility docstrings

Co-authored-by: varun-r-mallya <100590632+varun-r-mallya@users.noreply.github.com>

pythonbpf/expr/__init__.py

@@ -1,3 +1,5 @@
+"""Expression evaluation and processing for BPF programs."""
+
 from .expr_pass import eval_expr, handle_expr
 from .type_normalization import convert_to_bool
 

pythonbpf/expr/expr_pass.py

@@ -1,3 +1,11 @@
+"""
+Expression evaluation and LLVM IR generation.
+
+This module handles the evaluation of Python expressions in BPF programs,
+including variables, constants, function calls, comparisons, boolean
+operations, and more.
+"""
+
 import ast
 from llvmlite import ir
 from logging import Logger

pythonbpf/expr/type_normalization.py

@@ -1,3 +1,10 @@
+"""
+Type normalization and comparison operations for expressions.
+
+This module provides utilities for normalizing types between expressions,
+handling pointer dereferencing, and generating comparison operations.
+"""
+
 from llvmlite import ir
 import logging
 import ast