Updated README to include fallback.

Hi. Great repo. But I can't seem to work with the npx command. So, I updated the README.md to include a fallback for temporary purposes in case someone couldn't figure out what to do. This is of course temporary.

Author: Himujjal Upadhyaya

README.md

@@ -9,6 +9,11 @@ npm i @asgerf/dts-tree-sitter
 
 npx @asgerf/dts-tree-sitter INPUT > OUTPUT.d.ts
 ```
+If the above command fail:
+
+```sh
+node ./node_modules/@asgerf/dts-tree-sitter/build/src/index.js INPUT > OUTPUT.d.ts
+```
 
 where `INPUT` is used to locate a `node-types.json` file in one of the following locations:
 - `${INPUT}`
@@ -19,11 +24,18 @@ where `INPUT` is used to locate a `node-types.json` file in one of the following
 ## Example
 
 The `tree-sitter-javascript` grammar can be compiled like this:
+
 ```sh
 npm i tree-sitter-javascript
 npx @asgerf/dts-tree-sitter tree-sitter-javascript > generated.d.ts
 ```
 
+Fallback to the above command:
+
+```sh
+node ./node_modules/@asgerf/dts-tree-sitter/build/src/index.js tree-sitter-javascript > generated.d.ts
+```
+
 In the resulting grammar, two of the node types look like this:
 ```ts
 export interface ClassDeclarationNode extends SyntaxNodeBase {