[language] replace constant symbols with a constant value check function

test/tests/constant variable list.ans

@@ -1,4 +1,4 @@
-::a = *[3]
+:a::constant = *[3]
 
 |{a}
 

test/tests/constant variable.ans

@@ -1,4 +1,4 @@
-::a = 3
+:a::constant = 3
 
 {a}
 

test/tests/equality operator.ans

@@ -1,4 +1,4 @@
-::a = [1:2]
+:a::constant = [1:2]
 
 |false = {a == [5:2]}
 
@@ -6,7 +6,7 @@
 
 |true = {a == [1:2]}
 
-::b = [1,2,3]
+:b::constant = [1,2,3]
 
 |false = {b == a}
 
@@ -24,6 +24,6 @@
 
 |true = {c!to tuple == b}
 
-::d = [1,2,3]
+:d::constant = [1,2,3]
 
 |true = {d == b}

test/tests/symbol alias constant.ans

@@ -1,11 +1,11 @@
 :l = *[1,2,3]
 
-::&c => l(2)
+:&c::constant => l(2)
 
 | c={c} (2)
 | l={l} (*[1,2,3])
 
-::&d = "{l(2)}"
+:&d::constant = "{l(2)}"
 
 | d={c} (2)