doc: standardise the use of braces, brackets, and parens in asm source

parens () are used to specify object parent (e.g. the name of the class
that a message handler belongs to)

braces {} are used to specify the contents of an object (e.g. the
getter/setter for a property)

brackets [] are used to specify the identifier of an object (e.g. the
selector for a message handler)

doc/sample/Person.iasm

@@ -1,30 +1,30 @@
 @use std.io
 
-@lambda (Person_exampleProperty_get)
+@lambda [_.Person_exampleProperty_get]
 	ldr x0, [self, #2]
 	ret
 @end
 
-@lambda (Person_exampleProperty_set)
+@lambda [_.Person_exampleProperty_set]
 	ldr x0, [bp, #-1]
 	str x0, [self, #2]
 
 	ret
 @end
 
-@lambda (Person_exampleProperty3_get)
+@lambda [_.Person_exampleProperty3_get]
 	ldr x0, [self, #3]
 	ret
 @end
 
-@lambda (Person_exampleProperty3_set)
+@lambda [_.Person_exampleProperty3_set]
 	ldr x0, [bp, #-1]
 	str x0, [self, #3]
 
 	ret
 @end
 
-@lambda (Person_exampleProperty4_get)
+@lambda [_.Person_exampleProperty4_get]
 	ldr x0, [self, #4]
 	ret
 @end
@@ -39,20 +39,20 @@
 	#6: @atom[days]
 @end
 
-@class (net.doorstuck.test.Person)
-	$ exampleProperty (
-		get:Person_exampleProperty_get
-		set:Person_exampleProperty_set
-	)
+@class [net.doorstuck.test.Person]
+	$ exampleProperty {
+		get:_.Person_exampleProperty_get
+		set:_.Person_exampleProperty_set
+	}
 
-	$ exampleProperty2 (get:#42)
+	$ exampleProperty2 {get:#42}
 
-	$ exampleProperty3 (
-		get:Person_exampleProperty3_get
-		set:Person_exampleProperty3_set
-	)
+	$ exampleProperty3 {
+		get:_.Person_exampleProperty3_get
+		set:_.Person_exampleProperty3_set
+	}
 
-	$ exampleProperty4 (get:Person_exampleProperty4_get)
+	$ exampleProperty4 {get:_.Person_exampleProperty4_get}
 
 	#0: name
 	#1: age