Add readme for lezer-promql and update codemirror-promql readme (#10875)

Signed-off-by: Augustin Husson <husson.augustin@gmail.com>

web/ui/module/codemirror-promql/README.md

@@ -1,27 +1,17 @@
 CodeMirror-promql
 =================
-[![CircleCI](https://circleci.com/gh/prometheus/codemirror-promql.svg?style=shield)](https://circleci.com/gh/prometheus/codemirror-promql) [![GitHub license](https://img.shields.io/badge/license-Apache-blue.svg)](./LICENSE)
-[![NPM version](https://img.shields.io/npm/v/codemirror-promql.svg)](https://www.npmjs.org/package/codemirror-promql) [![codecov](https://codecov.io/gh/prometheus/codemirror-promql/branch/main/graph/badge.svg?token=rBHsyXshfl)](https://codecov.io/gh/prometheus/codemirror-promql)
-
-## Overview
 
 This project provides a mode for [CodeMirror Next](https://codemirror.net/6) that handles syntax highlighting, linting
 and autocompletion for PromQL ([Prometheus Query Language](https://prometheus.io/docs/introduction/overview/)).
 
 ![preview](https://user-images.githubusercontent.com/4548045/95660829-d5e4b680-0b2a-11eb-9ecb-41dca6396273.gif)
 
-## Where does it come from?
+## Installation
-
-The authoritative copy of this code lives in `prometheus/prometheus` and is synced to 
-`prometheus/codemirror-promql` on a regular basis by a bot. Please contribute any code changes to the code 
-in https://github.com/prometheus/prometheus/tree/main/web/ui/module/codemirror-promql.
-
-### Installation
 
 This mode is available as a npm package:
 
 ```bash
-npm install --save codemirror-promql
+npm install --save @prometheus-io/codemirror-promql
 ```
 
 **Note:** You will have to manually install different packages that are part
@@ -29,14 +19,14 @@ of [CodeMirror Next](https://codemirror.net/6), as they are a peer dependency to
 packages you need to install:
 
 * **@codemirror/autocomplete**
-* **@codemirror/highlight**
 * **@codemirror/language**
 * **@codemirror/lint**
 * **@codemirror/state**
 * **@codemirror/view**
+* **@lezer/common**
 
 ```bash
-npm install --save @codemirror/autocomplete @codemirror/highlight @codemirror/language @codemirror/lint @codemirror/state @codemirror/view
+npm install --save @codemirror/autocomplete @codemirror/language @codemirror/lint @codemirror/state @codemirror/view @lezer/common
 ```
 
 **Note 2**: that's the minimum required to install the lib. You would probably need to install as well the dependency
@@ -57,7 +47,7 @@ If you want to enjoy about the different features provided without taking too mu
 them, then the easiest way is this one:
 
 ```typescript
-import { PromQLExtension } from 'codemirror-promql';
+import {PromQLExtension} from '@prometheus-io/codemirror-promql';
 import {basicSetup} from '@codemirror/basic-setup';
 import {EditorState} from '@codemirror/state';
 import {EditorView} from '@codemirror/view';
@@ -173,7 +163,8 @@ const promQL = new PromQLExtension().setComplete({ remote: { httpMethod: 'GET' }
 
 ###### Override the API Prefix
 
-The default Prometheus Client, when building the query to get data from Prometheus, is using an API prefix which is by default `/api/v1`.
+The default Prometheus Client, when building the query to get data from Prometheus, is using an API prefix which is by
+default `/api/v1`.
 
 You can override this value like this:
 
@@ -246,4 +237,4 @@ Note: In case this parameter is provided, then the rest of the configuration is
 
 ## License
 
-Apache License 2.0, see [LICENSE](https://github.com/prometheus/codemirror-promql/blob/main/LICENSE).
+The code is licensed under an [Apache 2.0](https://github.com/prometheus/prometheus/blob/main/LICENSE) license.

web/ui/module/lezer-promql/README.md

@@ -0,0 +1,43 @@
+# lezer-promql
+
+## Overview
+
+This is a PromQL grammar for the [lezer](https://lezer.codemirror.net/) parser system. It is inspired by the initial
+grammar coming from [Prometheus](https://github.com/prometheus/prometheus/blob/main/promql/parser/generated_parser.y)
+written in yacc.
+
+This library is stable but doesn't provide any guideline of how to use it as it has been integrated
+into [codemirror-promql](https://github.com/prometheus/prometheus/blob/main/web/ui/module/codemirror-promql). If you
+want to use this library, you perhaps want to actually use **@prometheus-io/codemirror-promql** instead.
+
+**Note**: This library is a lezer-based implementation of the [authoritative, goyacc-based PromQL grammar](https://github.com/prometheus/prometheus/blob/main/promql/parser/generated_parser.y). 
+Any changes to the authoritative grammar need to be reflected in this package as well.
+
+## Installation
+
+This package is available as an npm package:
+
+```bash
+npm install --save @prometheus-io/lezer-promql
+```
+
+**Note**: you will have to manually install the `lezer` dependencies as it is a peer dependency to this package.
+
+```bash
+npm install --save @lezer/lr @lezer/highlight
+```
+
+## Development
+
+### Building
+
+    npm i
+    npm run build
+
+### Testing
+
+    npm run test
+
+## License
+
+The code is licensed under an [Apache 2.0](https://github.com/prometheus/prometheus/blob/main/LICENSE) license.