pre-commit: Rearrange the YAML file to avoid the warning

Having a root level key that existed only to make an anchor led to a warning,
instead create the anchor in the first place the key was used and then reference
it later on.

.pre-commit-config.yaml

@@ -1,29 +1,26 @@
 # See https://pre-commit.com for more information
 # See https://pre-commit.com/hooks.html for more hooks
 
-whitespace_excludes: &common_whitespace_excludes
-    # note: whitespace exclusions use multiline regex, see https://pre-commit.com/#regular-expressions
-    # items are:
-    # 1 - some file extensions
-    # 2 - any file matching *test*/*expected* (for host tests, if possible use this naming pattern always)
-    # 3 - any directory named 'testdata'
-    # 4 - IDF monitor test data
-    exclude: |
-        (?x)^(
-            .+\.(md|rst|map|bin)|
-            .+test.*\/.*expected.*|
-            .+\/testdata\/.+|
-            .+test_idf_monitor\/tests\/.+
-        )$
-
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v3.3.0
     hooks:
       - id: trailing-whitespace
-        <<: *common_whitespace_excludes
+        # note: whitespace exclusions use multiline regex, see https://pre-commit.com/#regular-expressions
+        # items are:
+        # 1 - some file extensions
+        # 2 - any file matching *test*/*expected* (for host tests, if possible use this naming pattern always)
+        # 3 - any directory named 'testdata'
+        # 4 - IDF monitor test data
+        exclude: &whitespace_excludes |
+            (?x)^(
+                .+\.(md|rst|map|bin)|
+                .+test.*\/.*expected.*|
+                .+\/testdata\/.+|
+                .+test_idf_monitor\/tests\/.+
+            )$
       - id: end-of-file-fixer
-        <<: *common_whitespace_excludes
+        exclude: *whitespace_excludes
       - id: check-executables-have-shebangs
       - id: file-contents-sorter
         files: 'tools/ci/executable-list.txt'