Code snippets use deprecated, internal syntax

[fbricon]

copied from microsoft/vscode#26834

in vscode 1.13, with snippets like

"Class Definition": {
    "prefix": "class",
    "body": [
      "/**",
      " * ${name}",
      " */",
      "public class ${name} {",
      "",
      "\tpublic ${name} (${parameters}) {",
      "\t\t$0",
      "\t}",
      "}"
    ],
    "description": "Class Definition"
  },

when selecting that template during completion, all parameters are gone now.

from @jrieken

The snippet above uses the internal syntax that we never documented and never made official. 
We have deprecated that in Nov 16 and are now removing support. I did create an adoption for 
item for your extensions and it seems to be closed: redhat-developer/vscode-java#99.

The new snippet syntax is TextMate like and defined here: 
https://code.visualstudio.com/docs/editor/userdefinedsnippets#_snippet-syntax

[fbricon]

While PR #218 fixes this particular issue, using autocompletion right in the middle of an inserted snippet is broken, see microsoft/vscode#26869