rust: stop claiming the C index is compatible with the rust code
This is no longer the case since the introduction of the pure Rust Index, and
was probably not the case since the MixedIndex itself.
So we fix the dedicated attribute value.
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2