Added i18n support for Thai

[icodeforlove]

Checklist

• All new and existing tests are passing
• (If adding features:) I have added tests to cover my changes
• (If docs changes needed:) I have updated the documentation accordingly.
• I have added an entry to CHANGES.rst because this is a user-facing change or an important bugfix
• I have written proper commit message(s)
  

What changes does this Pull Request introduce?

...

Why is this necessary?

...

[ix5]

Hey, thank you for contributing! You may have noticed that your code currently does nothing.

You have to add the Thai translation .js file to the translation list inside i18n.js and state which kind of plural form describes the Thai language most accurately.

By plural form we mean that depending on the count of a thing, the grammar also slightly changes.

For English, this would be:

• 0 apples
• One apple
• 2 apples
• 3 apples
• ... and so forth

Meaning that for a count of 0 and everything above 1, we say "apples", and only for 1, we say "apple". In code, this would be n !== 1 for the plural form and n === 1 for the singular form.

Here are two resources which might help:

• https://docs.translatehouse.org/projects/localization-guide/en/latest/l10n/pluralforms.html
• https://groups.drupal.org/node/5216

Here is my suggestion for you (you need to figure out where the correct pluralforms yourself):

diff --git a/isso/js/app/i18n.js b/isso/js/app/i18n.js
index 2579408..30a1632 100644
--- a/isso/js/app/i18n.js
+++ b/isso/js/app/i18n.js
@@ -28,6 +28,7 @@ var catalogue = {
     ru:      require("app/i18n/ru"),
     sk:      require("app/i18n/sk"),
     sv:      require("app/i18n/sv"),
+    th:      require("app/i18n/th"),
     tr:      require("app/i18n/tr"),
     uk:      require("app/i18n/uk"),
     vi:      require("app/i18n/vi"),
@@ -58,6 +59,7 @@ var pluralforms = function(lang) {
     case "nl":
     case "pt":
     case "sv":
+    case "th":
     case "tr":
     case "vi":
     case "zh":

For testing:

diff --git a/isso/demo/index.html b/isso/demo/index.html
index 1577253..cb4788d 100644
--- a/isso/demo/index.html
+++ b/isso/demo/index.html
@@ -11,6 +11,7 @@
 
    <script src="../js/embed.dev.js"
            data-isso="../"
+           data-isso-lang="th"
            ></script>
    <!-- Uncomment to only test count functionality: -->
    <!-- <script src="../js/count.dev.js"></script> -->