Documentation/maintainer-tip: Add C++ tail comments exception

Document when C++-style, tail comments should be used.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240130193102.GEZblOdor_bzoVhT0f@fat_crate.local

Author: bp3tk0v

Documentation/process/maintainer-tip.rst

@@ -480,7 +480,7 @@ Multi-line comments::
 	 * Larger multi-line comments should be split into paragraphs.
 	 */
 
-No tail comments:
+No tail comments (see below):
 
   Please refrain from using tail comments. Tail comments disturb the
   reading flow in almost all contexts, but especially in code::
@@ -501,6 +501,34 @@ No tail comments:
 	/* This magic initialization needs a comment. Maybe not? */
 	seed = MAGIC_CONSTANT;
 
+  Use C++ style, tail comments when documenting structs in headers to
+  achieve a more compact layout and better readability::
+
+        // eax
+        u32     x2apic_shift    :  5, // Number of bits to shift APIC ID right
+                                      // for the topology ID at the next level
+                                : 27; // Reserved
+        // ebx
+        u32     num_processors  : 16, // Number of processors at current level
+                                : 16; // Reserved
+
+  versus::
+
+	/* eax */
+	        /*
+	         * Number of bits to shift APIC ID right for the topology ID
+	         * at the next level
+	         */
+         u32     x2apic_shift    :  5,
+		 /* Reserved */
+				 : 27;
+
+	/* ebx */
+		/* Number of processors at current level */
+	u32     num_processors  : 16,
+		/* Reserved */
+				: 16;
+
 Comment the important things:
 
   Comments should be added where the operation is not obvious. Documenting