Merge bitcoin#23493: Use c++17 in clang-format

faeb748 Use c++17 in clang-format (MarcoFalke)

Pull request description:

  We currently use `Cpp11`, which "is a deprecated alias for `Latest`" according to https://clang.llvm.org/docs/ClangFormatStyleOptions.html . I doubt this has any effect, but I think for clarity setting to `c++17` make sense.

  Also, remove unneeded settings:

  * `ObjC*`, as we don't write objc code
  * `Penalty`, as there is currently no line limit, so this has no effect
  * `TabWidth`, as we don't use tabs

ACKs for top commit:
  fanquake:
    ACK faeb748 - we do have some Objc code, but it never changes.

Tree-SHA512: 50215849b3992e5841b45b281e68d4c58184a365cbaeec0d7adad844ad21672ae1b6247262047e2d7427835ef98fa9d9f83335696448c77303dde9ab0a121639

src/.clang-format

@@ -34,14 +34,6 @@ IndentWidth:     4
 KeepEmptyLinesAtTheStartOfBlocks: false
 MaxEmptyLinesToKeep: 2
 NamespaceIndentation: None
-ObjCSpaceAfterProperty: false
-ObjCSpaceBeforeProtocolList: false
-PenaltyBreakBeforeFirstCallParameter: 1
-PenaltyBreakComment: 300
-PenaltyBreakFirstLessLess: 120
-PenaltyBreakString: 1000
-PenaltyExcessCharacter: 1000000
-PenaltyReturnTypeOnItsOwnLine: 200
 PointerAlignment: Left
 SpaceBeforeAssignmentOperators: true
 SpaceBeforeParens: ControlStatements
@@ -51,6 +43,5 @@ SpacesInAngles:  false
 SpacesInContainerLiterals: true
 SpacesInCStyleCastParentheses: false
 SpacesInParentheses: false
-Standard:        Cpp11
-TabWidth:        8
+Standard:        c++17
 UseTab:          Never