Dissociate ECLiPSe from Prolog

ECLiPSe syntax is slightly different from Prolog syntax
ECLiPSe is in the Prolog group so it will only be highlighted differently

lib/linguist/heuristics.rb

@@ -112,7 +112,7 @@ module Linguist
 
     disambiguate ".ecl" do |data|
       if /^[^#]+:-/.match(data)
-        Language["Prolog"]
+        Language["ECLiPSe"]
       elsif data.include?(":=")
         Language["ECL"]
       end

lib/linguist/languages.yml

@@ -843,6 +843,14 @@ ECL:
   tm_scope: none
   ace_mode: text
 
+ECLiPSe:
+  type: programming
+  group: prolog
+  extensions:
+  - .ecl
+  tm_scope: source.prolog.eclipse
+  ace_mode: prolog
+
 Eagle:
   type: markup
   color: "#814C05"
@@ -2628,7 +2636,6 @@ Prolog:
   color: "#74283c"
   extensions:
   - .pl
-  - .ecl
   - .pro
   - .prolog
   interpreters:

test/test_heuristics.rb

@@ -66,11 +66,11 @@ class TestHeuristcs < Minitest::Test
     })
   end
 
-  # Candidate languages = ["ECL", "Prolog"]
+  # Candidate languages = ["ECL", "ECLiPSe"]
-  def test_ecl_prolog_by_heuristics
+  def test_ecl_by_heuristics
     assert_heuristics({
       "ECL" => all_fixtures("ECL", "*.ecl"),
-      "Prolog" => all_fixtures("Prolog", "*.ecl")
+      "ECLiPSe" => all_fixtures("ECLiPSe", "*.ecl")
     })
   end