[MG_Backend] (DirectGLES): the guard comment cites the visibility block it means

Two comments from the previous commit, corrected. The CMakeLists.txt reference in
DirectGLES.cpp pointed at the link libraries instead of the Debug/Release
visibility preset it names (707-719, not 629-641). The Managers.h note said the
overload is "reached by the pull, verify and push build" through "the three
wrappers", which reads as if all three called it; only
VertexArrayImpl::SyncClientSideVertexArraysForFetch does, and what those flavors
compile is the declaration, which is the point being made.

No code change: the four flavors' libraries are byte-identical to the previous
commit's (comment-only).

MobileGL/MG_Backend/DirectGLES/DirectGLES.cpp

@@ -2423,7 +2423,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // function that only re-homes two identical inline blocks the two DrawArrays entry
         // points used to carry. The same spelling governs the three below, and for a second
         // reason on top of the symbol count: a Debug build drops CXX_VISIBILITY_PRESET to
-        // `default` (CMakeLists.txt:629-641), so an external-linkage helper here would be a
+        // `default` (CMakeLists.txt:707-719), so an external-linkage helper here would be a
         // DYNAMIC export in exactly the configuration a symbol gate cannot see it in.
         //
         // ALL FLAVORS, NOT JUST THE SPLIT ARM. These three were inside

MobileGL/MG_Backend/DirectGLES/Managers.h

@@ -1358,11 +1358,12 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // SKIP the draw: issuing it would have the shader read whatever the ES context last
             // held for that attribute, which is a wrong picture rather than an error.
             //
-            // UNGUARDED WITH ITS CALLERS: the three VertexArrayImpl wrappers above it in
+            // UNGUARDED WITH ITS CALLERS. Its only call site is
-            // DirectGLES.cpp early-return unless the transport is Monolith, so this overload is
+            // VertexArrayImpl::SyncClientSideVertexArraysForFetch in DirectGLES.cpp, whose
-            // reached by the pull, verify and push build too - and those builds compile the
+            // body returns early unless the transport is Monolith - and the monolith arm is
-            // indexed and indirect entry points that call it. The declaration follows its
+            // what the pull, verify and push builds run, not a split-arm fallback. Those
-            // definition (Managers.cpp).
+            // flavors therefore compile it, so its declaration and definition (Managers.cpp)
+            // have to be visible there too.
             Bool SyncClientSideAttributesForDraw(
                 const SharedPtr<MG_State::GLState::VertexArrayObject>& stateVAOObject,
                 const MG_Pipe::MGPipeClientFetchPlan& plan, Uint32 fetchBaseInstance);