Fix pin_all_from incorrectly removing "js" substring from filenames

When using pin_all_from, filenames containing "js" as a substring
(like "foo.jszip.js" or "bar.jsmin.js") were having the substring
incorrectly removed, resulting in malformed module names like
"foozip" and "barmin" instead of "foo.jszip" and "bar.jsmin".

Fixed the logic to only remove the file extension from the end
of the filename, preserving any "js" substrings that appear
elsewhere in the name.

Fixes #282

Author: rafaelfranca

lib/importmap/map.rb

@@ -302,7 +302,7 @@ def module_name_from(filename, mapping)
       # folder/index
       index_regex = /(?:\/|^)index$/
 
-      [ mapping.under, filename.to_s.remove(filename.extname).remove(index_regex).presence ].compact.join("/")
+      [ mapping.under, filename.to_s.chomp(filename.extname).remove(index_regex).presence ].compact.join("/")
     end
 
     def module_path_from(filename, mapping)

test/dummy/app/javascript/controllers/bar.jsmin.js

@@ -0,0 +1 @@
+export function testJsmin() { return 'jsmin test'; }

test/dummy/app/javascript/controllers/foo.jszip.js

@@ -0,0 +1 @@
+export function testJszip() { return 'jszip test'; }

test/importmap_test.rb

@@ -134,6 +134,17 @@ def setup
     assert_match %r|assets/my_lib-.*\.js|, generate_importmap_json["imports"]["my_lib"]
   end
 
+  test "pin_all_from handles filenames with js substring correctly" do
+    assert_includes generate_importmap_json["imports"].keys, "controllers/foo.jszip"
+    assert_includes generate_importmap_json["imports"].keys, "controllers/bar.jsmin"
+
+    refute_includes generate_importmap_json["imports"].keys, "controllers/foozip"
+    refute_includes generate_importmap_json["imports"].keys, "controllers/barmin"
+
+    assert_match %r|assets/controllers/foo\.jszip-.*\.js|, generate_importmap_json["imports"]["controllers/foo.jszip"]
+    assert_match %r|assets/controllers/bar\.jsmin-.*\.js|, generate_importmap_json["imports"]["controllers/bar.jsmin"]
+  end
+
   test "importmap json includes integrity hashes from integrity: true" do
     importmap = Importmap::Map.new.tap do |map|
       map.enable_integrity!