Wires signature help to codemirror (#157)

Author: ncordon

.changeset/twelve-cycles-call.md

@@ -0,0 +1,5 @@
+---
+'@neo4j-cypher/language-support': patch
+---
+
+Adds signature help capabilities to the language support

.vscode/settings.json

@@ -2,7 +2,7 @@
   "typescript.tsc.autoDetect": "off",
   "typescript.preferences.quoteStyle": "single",
   "editor.codeActionsOnSave": {
-    "source.fixAll.eslint": true
+    "source.fixAll.eslint": "explicit"
   },
   "editor.defaultFormatter": "esbenp.prettier-vscode",
   "editor.formatOnSave": true,