[COMMITTED] ada: Improve comment on First_Entity

[COMMITTED] ada: Improve comment on First_Entity

[Marc Poulhiès]

From: Bob Duff <duff@adacore.com>

Clarify that "act as scope" overlaps with "[sub]type".

gcc/ada/

	* einfo.ads:
	(First_Entity): Update comment explaining why this exists on all
	[sub]types, as opposed to just the ones with associated entities.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/einfo.ads | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/gcc/ada/einfo.ads b/gcc/ada/einfo.ads
index 878737c7cc1..6748533a32c 100644
--- a/gcc/ada/einfo.ads
+++ b/gcc/ada/einfo.ads
@@ -1347,11 +1347,12 @@ package Einfo is
 
 --    First_Entity
 --       Defined in all entities that act as scopes to which a list of
---       associated entities is attached. This is defined in all [sub]types,
---       including things like scalars that cannot have nested entities,
---       which makes it more convenient to Mutate_Entity between type kinds.
---       Points to a list of associated entities using the Next_Entity field
---       as a chain pointer with Empty marking the end of the list.
+--       associated entities is attached, and also in all [sub]types. Some
+--       entities are both; for example E_Record_Type acts as a scope and
+--       is a type. [Sub]types that do not act as scopes (e.g. scalars) are
+--       included to make it more convenient to Mutate_Entity between type
+--       kinds. Points to a list of associated entities linked through the
+--       Next_Entity field with Empty marking end-of-list.
 --       See also Last_Entity.
 
 --    First_Exit_Statement
-- 
2.40.0