docs: improve docstring for string_literal function for clarity

Author: kosiew

docs/source/user-guide/common-operations/functions.rst

@@ -38,7 +38,7 @@ DataFusion offers mathematical functions such as :py:func:`~datafusion.functions
 
 .. ipython:: python
 
-    from datafusion import col, literal, utf8_literal
+    from datafusion import col, literal, string_literal
     from datafusion import functions as f
 
     df.select(
@@ -112,8 +112,8 @@ Casting expressions to different data types using :py:func:`~datafusion.function
 .. ipython:: python
 
     df.select(
-        f.arrow_cast(col('"Total"'), utf8_literal("Float64")).alias("total_as_float"),
-        f.arrow_cast(col('"Total"'), utf8_literal("Int32")).alias("total_as_int")
+        f.arrow_cast(col('"Total"'), string_literal("Float64")).alias("total_as_float"),
+        f.arrow_cast(col('"Total"'), str_lit("Int32")).alias("total_as_int")
     )
 
 Other

python/datafusion/__init__.py

@@ -109,13 +109,14 @@ def literal(value):
 
 def string_literal(value):
     """Create a UTF8 literal expression.
-    It differs from `literal`  creates a UTF8view literal.
+
+    It differs from `literal` which creates a UTF8view literal.
     """
     return Expr.string_literal(value)
 
 
 def str_lit(value):
-    """Alias for `string_literal`"""
+    """Alias for `string_literal`."""
     return string_literal(value)