Recommend 4 spaces for indentation in the style guide.

Users shouldn't worry too much about it, we will soon recommend
using Buildifier.

RELNOTES: None.
PiperOrigin-RevId: 196025297

site/docs/skylark/bzl-style.md

@@ -45,7 +45,9 @@ to make your files easy to process, both by humans and tools.
 
 
 *   When in doubt, follow the [Python style
-    guide](https://www.python.org/dev/peps/pep-0008/).
+    guide](https://www.python.org/dev/peps/pep-0008/). In particular, use 4
+    4 spaces for indentation (we previously recommended 2, but we now
+    follow the Python convention).
 
 *   Document files and functions using [docstrings](skylint.md#docstrings). Use
     a docstring at the top of each `.bzl` file, and a docstring for each public
@@ -69,12 +71,12 @@ to make your files easy to process, both by humans and tools.
 
 ```python
 def fct(name, srcs):
-  filtered_srcs = my_filter(source=srcs)
-  native.cc_library(
-    name = name,
-    srcs = filtered_srcs,
-    testonly = True,
-  )
+    filtered_srcs = my_filter(source = srcs)
+    native.cc_library(
+        name = name,
+        srcs = filtered_srcs,
+        testonly = True,
+    )
 ```
 
 *   Prefer values `True` and `False` instead of `0` and `1` for boolean values