manual.yml: fix references to javascript, and clarify semantics of == (#2645)

remove inaccurate and confusing references to javascript; clarify semantics of ==

tests/man.test

@@ -668,6 +668,14 @@ strptime("%Y-%m-%dT%H:%M:%SZ")|mktime
 "2015-03-05T23:51:47Z"
 1425599507
 
+. == false
+null
+false
+
+. == {"b": {"d": (4 + 1e-20), "c": 3}, "a":1}
+{"a":1, "b": {"c": 3, "d": 4}}
+true
+
 .[] == 1
 [1, 1.0, "1", "banana"]
 true