[clang-format] Always add a space after #if and #elif (llvm#81578)

Fixes llvm#81569.

Author: owenca

clang/lib/Format/TokenAnnotator.cpp

@@ -1856,6 +1856,8 @@ class AnnotatingParser {
     case tok::pp_elif:
       Contexts.back().IsExpression = true;
       next();
+      if (CurrentToken)
+        CurrentToken->SpacesRequiredBefore = true;
       parseLine();
       break;
     default:

clang/unittests/Format/FormatTest.cpp

@@ -16491,6 +16491,10 @@ TEST_F(FormatTest, ConfigurableSpaceBeforeParens) {
   verifyFormat("T A::operator()();", NoSpace);
   verifyFormat("X A::operator++(T);", NoSpace);
   verifyFormat("auto lambda = []() { return 0; };", NoSpace);
+  verifyFormat("#if (foo || bar) && baz\n"
+               "#elif ((a || b) && c) || d\n"
+               "#endif",
+               NoSpace);
 
   FormatStyle Space = getLLVMStyle();
   Space.SpaceBeforeParens = FormatStyle::SBPO_Always;