Support for .pro INI files (KiCad project files)

Update the heuristic for .pro to include both INI and QMake files
Fixes #2116

lib/linguist/heuristics.rb

@@ -107,10 +107,14 @@ module Linguist
       end
     end
 
-    disambiguate "IDL", "Prolog" do |data|
+    disambiguate "IDL", "Prolog", "INI", "QMake" do |data|
       if data.include?(":-")
         Language["Prolog"]
-      else
+      elsif data.include?("last_client=")
+        Language["INI"]
+      elsif data.include?("HEADERS") && data.include?("SOURCES")
+        Language["QMake"]
+      elsif /^\s*function[ \w,]+$/.match(data)
         Language["IDL"]
       end
     end

lib/linguist/languages.yml

@@ -1311,6 +1311,7 @@ INI:
   - .ini
   - .cfg
   - .prefs
+  - .pro
   - .properties
   tm_scope: source.ini
   aliases: