[clang-format] Keep the space between not and a unary operator (#135035)

Also keep the space between `not` and `::`.

Based on the
[documentation](https://releases.llvm.org/20.1.0/tools/clang/docs/ClangFormatStyleOptions.html#spaceafterlogicalnot),
it can be argued that SpaceAfterLogicalNot doesn't cover the alternative
operator `not`.

Closes #125465

Author: owenca

clang/lib/Format/TokenAnnotator.cpp

@@ -5472,7 +5472,12 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
     // handled.
     if (Left.is(tok::amp) && Right.is(tok::r_square))
       return Style.SpacesInSquareBrackets;
-    return Style.SpaceAfterLogicalNot && Left.is(tok::exclaim);
+    if (Left.isNot(tok::exclaim))
+      return false;
+    if (Left.TokenText == "!")
+      return Style.SpaceAfterLogicalNot;
+    assert(Left.TokenText == "not");
+    return Right.isOneOf(tok::coloncolon, TT_UnaryOperator);
   }
 
   // If the next token is a binary operator or a selector name, we have

clang/unittests/Format/FormatTest.cpp

@@ -25393,16 +25393,17 @@ TEST_F(FormatTest, AlternativeOperators) {
   verifyFormat("%:define ABC abc"); // #define ABC abc
   verifyFormat("%:%:");             // ##
 
+  verifyFormat("return not ::f();");
+  verifyFormat("return not *foo;");
+
   verifyFormat("a = v(not;);\n"
-               "b = v(not+);\n"
                "c = v(not x);\n"
                "d = v(not 1);\n"
                "e = v(not 123.f);");
 
   verifyNoChange("#define ASSEMBLER_INSTRUCTION_LIST(V)  \\\n"
                  "  V(and)                               \\\n"
                  "  V(not)                               \\\n"
-                 "  V(not!)                              \\\n"
                  "  V(other)",
                  getLLVMStyleWithColumns(40));
 }