Add switch header/source to editor context menu

Author: vaivaswatha

package.json

@@ -252,6 +252,10 @@
                     "group": "0_navigation@4",
                     "_comment": "see https://github.com/microsoft/vscode-references-view/blob/f63eaed9934ca5ecc8f3fb3ca096f38c6e5e181f/package.json#L162"
                 },
+		{
+		    "command": "clangd.switchheadersource",
+		    "group": "0_navigation@5"
+		},
                 {
                     "command": "clangd.ast",
                     "when": "clangd.ast.supported"