feat(org-mode): add inline src snippet

* Add Inline Source Snippet

* Add Placeholder Hints

Use placeholders to illustrate fields of inline source blocks.

Author: 1submarine

org-mode/inline_source

@@ -0,0 +1,7 @@
+# -*- mode: snippet -*-
+# name: Inline Source
+# uuid: srci
+# key: srci
+# condition: t
+# --
+src_${1:language}[${2:header}]{${0:body}}