Add BasedOnStyle key to ClangFormat configuration

The ClangFormat configuration file was previously generated using ClangFormat 11.0.1. The output produced by that
version did not contain a `BasedOnStyle` key, which is why it was not present in the configuration despite being
supported by 11.0.1. Since Arduino's configuration sets all configuration keys, the `BasedOnStyle` key has no effect
anyway.

The configuration file generated using ClangFormat 14.0.0 does contain a `BasedOnStyle` key. Unfortunately, regardless
of what was set in the configuration, the tool always outputs a key set to an empty string. Even though it is likely not
an issue, this is concerning because it is not documented as a supported value.

Author: per1234

other/clang-format-configuration/.clang-format

@@ -26,6 +26,7 @@ AlwaysBreakBeforeMultilineStrings: false
 AlwaysBreakTemplateDeclarations: No
 AttributeMacros:
   - __capability
+BasedOnStyle: ''
 BinPackArguments: true
 BinPackParameters: true
 BitFieldColonSpacing: Both

other/clang-format-configuration/notes.md

@@ -14,7 +14,7 @@ It is not clear from the documentation, but this truly is an "allow" setting, ra
 
 This key is irrelevant because we define all configuration keys.
 
-**ClangFormat** uses the `LLVM` style as a base by default.
+Even though it is not one of the documented possible values, `clang-format --dump-config` outputs `BasedOnStyle: ''`, so we use that.
 
 ## `BraceWrapping`