[create-pull-request] automated change (#732)

Co-authored-by: RexJaeschke <[email protected]>

Author: github-actions[bot]

standard/classes.md

@@ -444,11 +444,11 @@ The value type constraint specifies that a type argument used for the type param
 
 > *Note*: The `System.Nullable<T>` type specifies the non-nullable value type constraint for `T`. Thus, recursively constructed types of the forms `T??` and `Nullable<Nullable<T>>` are prohibited. *end note*
 
-Because `unmanaged` is not a keyword, in *primary_constraint* the unmanaged constraint is always syntactically ambiguous with *class_type*. For compatibility reasons, if a name lookup (§11.7.4) of the name `unmanaged` succeeds it is treated as a `class_type`. Otherwise it is treated as the unmanaged constraint.
+Because `unmanaged` is not a keyword, in *primary_constraint* the unmanaged constraint is always syntactically ambiguous with *class_type*. For compatibility reasons, if a name lookup ([§11.7.4](expressions.md#1174-simple-names)) of the name `unmanaged` succeeds it is treated as a `class_type`. Otherwise it is treated as the unmanaged constraint.
 
 The unmanaged type constraint specifies that a type argument used for the type parameter shall be a non-nullable unmanaged type ([§8.8](types.md#88-unmanaged-types)).
 
-Pointer types are never allowed to be type arguments, and don't satisfy any type constraints, even unmanaged, despite being unmanaged types.
+Pointer types are never allowed to be type arguments, and don’t satisfy any type constraints, even unmanaged, despite being unmanaged types.
 
 If a constraint is a class type, an interface type, or a type parameter, that type specifies a minimal “base type” that every type argument used for that type parameter shall support. Whenever a constructed type or generic method is used, the type argument is checked against the constraints on the type parameter at compile-time. The type argument supplied shall satisfy the conditions described in [§8.4.5](types.md#845-satisfying-constraints).
 

standard/grammar.md

@@ -207,12 +207,12 @@ keyword
 
 // Source: §6.4.4 Keywords
 contextual_keyword
-    : 'add'    | 'alias'      | 'ascending' | 'async'   | 'await'
-    | 'by'     | 'descending' | 'dynamic'   | 'equals'  | 'from'
-    | 'get'    | 'global'     | 'group'     | 'into'    | 'join'
-    | 'let'    | 'nameof'     | 'on'        | 'orderby' | 'partial'
-    | 'remove' | 'select'     | 'set'       | 'value'   | 'var'
-    | 'when'   | 'where'      | 'yield'
+    : 'add'    | 'alias'      | 'ascending' | 'async'     | 'await'
+    | 'by'     | 'descending' | 'dynamic'   | 'equals'    | 'from'
+    | 'get'    | 'global'     | 'group'     | 'into'      | 'join'
+    | 'let'    | 'nameof'     | 'on'        | 'orderby'   | 'partial'
+    | 'remove' | 'select'     | 'set'       | 'unmanaged' | 'value'
+    | 'var'    | 'when'       | 'where'     | 'yield'
     ;
 
 // Source: §6.4.5.1 General
@@ -1804,6 +1804,7 @@ primary_constraint
     : class_type
     | 'class'
     | 'struct'
+    | 'unmanaged'
     ;
 
 secondary_constraints