[lld] [LLD] Add CLASS syntax to SECTIONS (PR #95323)

[Daniel Thornburgh via llvm-commits]

================
@@ -198,13 +198,52 @@ the current location to a max-page-size boundary, ensuring that the next
 LLD will insert ``.relro_padding`` immediately before the symbol assignment
 using ``DATA_SEGMENT_RELRO_END``.
 
+Section Classes
+~~~~~~~~~~~~~~~
+
+``SECTIONS`` commands can define classes of input sections:
+
+::
+
+  SECTIONS {
+    CLASS(class_name) {
+      input-section-description
+      input-section-description
+      ...
+    }
+  }
+
+Input section descriptions can refer to a class using ``CLASS(class_name)``
+instead of the usual filename and section name patterns. For example:
----------------
mysterymath wrote:

Added a parsing test; I think "a class" and the singularity of "class_name" should be sufficient on the doc side.

https://github.com/llvm/llvm-project/pull/95323