Add documentation for =: as an inline pattern match

backend/Builtin/Syntax.icl

@@ -38,7 +38,7 @@ builtin_syntax =
 	, bs_newtype
 	, bs_overloaded_type_variable
 	, bs_otherwise
-	, bs_pattern_named
+	, bs_pattern
 	, bs_selection_array
 	, bs_selection_array_unique
 	, bs_selection_record
@@ -427,15 +427,16 @@ bs_otherwise =
 		]
 	}
 
-bs_pattern_named =
-	{ syntax_title         = "named pattern match"
+bs_pattern =
+	{ syntax_title         = "pattern match"
 	, syntax_patterns      = ["=:"]
 	, syntax_code          = ["...=:(...)"]
-	, syntax_description   = "Give a name to the expression of a pattern to be able to use the whole expression without creating new graphs."
+	, syntax_description   = "Give a name to the expression of a pattern to be able to use the whole expression without creating new graphs. This can also be used to check if a value (not a function argument) matches a pattern (undocumented and you can not use identifiers). `=:` can not be used in prefix form because it is not an actual operator but a builtin."
 	, syntax_doc_locations = [CLR 5 "3.2" "_Toc311797997"]
 	, syntax_examples      =
 		[ EXs "macro" "isJustU e=:(Just _) = (True, e) // On an ADT"
 		, EX          ":: Position = {px :: Int, py :: Int}\ngetx p=:{px} = (px, p) // On a record; this has type :: Position -> (Int, Position)"
+		, EX          "isSingleton l = l =: [_] //Match a value with a pattern"
 		]
 	}