[css] Add some docstrings following "did you mean" PR feedback

src/textual/css/_styles_builder.py

@@ -119,6 +119,11 @@ class StylesBuilder:
         """
         Returns the list of CSS properties we can manage -
         i.e. the ones for which we have a `process_[property name]` method
+
+        Returns:
+            Sequence[str]: All the "Python-ised" CSS property names this class can handle.
+
+        Example: ("width", "background", "offset_x", ...)
         """
         return [attr[8:] for attr in dir(self) if attr.startswith("process_")]
 
@@ -751,6 +756,13 @@ class StylesBuilder:
         """
         Returns a valid CSS property "Python" name, or None if no close matches could be found.
 
+        Args:
+            rule_name (str): An invalid "Python-ised" CSS property (i.e. "offst_x" rather than "offst-x")
+
+        Returns:
+            str | None: The closest valid "Python-ised" CSS property.
+                Returns `None` if no close matches could be found.
+
         Example: returns "background" for rule_name "bkgrund", "offset_x" for "ofset_x"
         """
         return get_suggestion(rule_name, self._get_processable_rule_names())

src/textual/suggestions.py

@@ -6,7 +6,14 @@ from typing import Sequence
 
 def get_suggestion(word: str, possible_words: Sequence[str]) -> str | None:
     """
-    Returns a close match of 'word' amongst 'possible_words', or None if no close matches could be found.
+    Returns a close match of `word` amongst `possible_words`.
+
+    Args:
+        word (str): The word we want to find a close match for
+        possible_words (Sequence[str]): The words amongst which we want to find a close match
+
+    Returns:
+        str | None: The closest match amongst the `possible_words`. Returns `None` if no close matches could be found.
 
     Example: returns "red" for word "redu" and possible words ("yellow", "red")
     """
@@ -16,8 +23,15 @@ def get_suggestion(word: str, possible_words: Sequence[str]) -> str | None:
 
 def get_suggestions(word: str, possible_words: Sequence[str], count: int) -> list[str]:
     """
-    Returns a list of up to 'count' matches of 'word' amongst 'possible_words' -
-    or an empty list if no close matches could be found.
+    Returns a list of up to `count` matches of `word` amongst `possible_words`.
+
+    Args:
+        word (str): The word we want to find a close match for
+        possible_words (Sequence[str]): The words amongst which we want to find close matches
+
+    Returns:
+        list[str]: The closest matches amongst the `possible_words`, from the closest to the least close.
+            Returns an empty list if no close matches could be found.
 
     Example: returns ["yellow", "ellow"] for word "yllow" and possible words ("yellow", "red", "ellow")
     """