docs: Add caveat about gap and padding not being used unless the navbar is fillable (#1673)

Author: schloerke

shiny/ui/_navs.py

@@ -1200,7 +1200,7 @@ def navset_bar(
         provided, `fillable` makes the main content portion fillable.
     gap
         A CSS length unit defining the gap (i.e., spacing) between elements provided to
-        `*args`.
+        `*args`. This value is only used when the navbar is `fillable`.
     padding
         Padding to use for the body. This can be a numeric vector (which will be
         interpreted as pixels) or a character vector with valid CSS lengths. The length
@@ -1209,7 +1209,7 @@ def navset_bar(
         the second value will be used for left and right. If three, then the first will
         be used for top, the second will be left and right, and the third will be
         bottom. If four, then the values will be interpreted as top, right, bottom, and
-        left respectively.
+        left respectively. This value is only used when the navbar is `fillable`.
     position
         Determines whether the navbar should be displayed at the top of the page with
         normal scrolling behavior ("static-top"), pinned at the top ("fixed-top"), or

shiny/ui/_page.py

@@ -196,6 +196,18 @@ def page_navbar(
         (i.e., flexbox) container.
     fillable_mobile
         Whether or not ``fillable`` should apply on mobile devices.
+    gap
+        A CSS length unit defining the gap (i.e., spacing) between elements provided to
+        `*args`. This value is only used when the navbar is _fillable_.
+    padding
+        Padding to use for the body. This can be a numeric vector (which will be
+        interpreted as pixels) or a character vector with valid CSS lengths. The length
+        can be between one and four. If one, then that value will be used for all four
+        sides. If two, then the first value will be used for the top and bottom, while
+        the second value will be used for left and right. If three, then the first will
+        be used for top, the second will be left and right, and the third will be
+        bottom. If four, then the values will be interpreted as top, right, bottom, and
+        left respectively. This value is only used when the navbar is _fillable_.
     position
         Determines whether the navbar should be displayed at the top of the page with
         normal scrolling behavior ("static-top"), pinned at the top ("fixed-top"), or