ruff_annotate_snippets: update snapshot for single ASCII whitespace source

The change to the rendering code is elaborated on in more detail here,
where I attempted to upstream it:
rust-lang/annotate-snippets-rs#169

Otherwise, the snapshot diff also shows a bug fix: a `^` is now rendered
where as it previously was not.

Author: BurntSushi

crates/ruff_annotate_snippets/src/renderer/display_list.rs

@@ -1394,9 +1394,7 @@ fn format_body(
                 }
             })
             .sum();
-        if line.chars().any(|c| !c.is_whitespace()) {
-            whitespace_margin = min(whitespace_margin, leading_whitespace);
-        }
+        whitespace_margin = min(whitespace_margin, leading_whitespace);
         max_line_len = max(max_line_len, line_length);
 
         let line_start_index = line_range.0;

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__w292_4.snap

@@ -1,11 +1,10 @@
 ---
 source: crates/ruff_linter/src/rules/pycodestyle/mod.rs
-snapshot_kind: text
 ---
 W292_4.py:1:2: W292 [*] No newline at end of file
   |
 1 |  
-  |   W292
+  |  ^ W292
   |
   = help: Add trailing newline