add prepend option to glossary definition tag

_plugins/README.md

@@ -25,6 +25,7 @@ This renders the definition of the glossary term inside a `<div>`, preserving Ma
 | --- | --- | --- |
 | `term_id` | N/A (Required) | The `id` of the glossary term whose definition will be used. (This `id` is the same as the filename of the term, i.e. `_data/glossary/<ID>.yml`.) |
 | `length` | "short" | Specifies which term definition should be used ("short" for the `short-definition`, "long" for `long-description`, "all" when both should be included). |
+| `prepend` | "Service Catalog is" | A prefix which can be attached in front of a term's short definition (which is one or more sentence fragments). |
 
 #### (2) `glossary_tooltip` tag
 

_plugins/glossary_tags.rb

@@ -55,11 +55,17 @@ module Jekyll
     class Definition < Base
       VALID_PARAM_NAMES = [
         :term_id,
-        :length
+        :length,
+        :prepend,
       ].freeze
 
       def render(context)
-        include_snippet(context)
+        text = include_snippet(context)
+        if @args[:prepend]
+          text.sub(/<p>(.)/) { "<p>#{@args[:prepend]} #{$1.downcase}" }
+        else
+          text
+        end
       end
     end