Add explicit "# key" directive to legacy snippet collection before deprecating filenames-as-triggers

snippets/emacs-lisp-mode/x-dired.process_marked.yasnippet

@@ -1,5 +1,6 @@
 #contributor: Xah Lee (XahLee.org)
 #name: process marked files in dired
+# key: x-dired
 # --
 ;; idiom for processing a list of files in dired's marked files
  

snippets/emacs-lisp-mode/x-file.process.yasnippet

@@ -1,5 +1,6 @@
 #contributor: Xah Lee (XahLee.org)
 #name: a function that process a file
+# key: x-file
 # --
 (defun doThisFile (fpath)
   "Process the file at path FPATH ..."

snippets/emacs-lisp-mode/x-file.read-lines.yasnippet

@@ -1,5 +1,6 @@
 #contributor: Xah Lee (XahLee.org)
 #name: read lines of a file
+# key: x-file
 # --
 (defun read-lines (filePath)
   "Return a list of lines in FILEPATH."

snippets/emacs-lisp-mode/x-find-replace.yasnippet

@@ -1,5 +1,6 @@
 #contributor: Xah Lee (XahLee.org)
 #name: find and replace on region
+# key: x-find-replace
 # --
 (defun replace-html-chars-region (start end)
   "Replace “<” to “&lt;” and other chars in HTML.

snippets/emacs-lisp-mode/x-grabstring.yasnippet

@@ -1,4 +1,5 @@
 #contributor: Xah Lee (XahLee.org)
 #name: grab buffer substring
+# key: x-grabstring
 # --
 (setq $0 (buffer-substring-no-properties myStartPos myEndPos))

snippets/emacs-lisp-mode/x-grabthing.yasnippet

@@ -1,4 +1,5 @@
 #contributor: Xah Lee (XahLee.org)
 #name: grab word under cursor
+# key: x-grabthing
 # --
 (setq $0 (thing-at-point 'symbol))

snippets/emacs-lisp-mode/x-traverse_dir.yasnippet

@@ -1,5 +1,6 @@
 #name: traversing a directory
 #contributor: Xah Lee (XahLee.org)
+# key: x-traverse_dir
 # --
 ;; apply a function to all files in a dir
 (require 'find-lisp)

snippets/emacs-lisp-mode/x-word-or-region.yasnippet

@@ -1,5 +1,6 @@
 #contributor: Xah Lee (XahLee.org)
 #name: Command that works on region or word
+# key: x-word-or-region
 # --
 ;; example of a command that works on current word or text selection
 (defun down-case-word-or-region ()