[monorepo] rebuild lezer output as part of 'make install' (#28545)

* [monorepo] rebuild lezer output as part of 'make install'

* [monorepo] run 'make install' with high concurrency in Jenkins

* [monorepo] rebuild lezer parser output once

* [monorepo] headless npm run

* [web] update docs for lezer

GitOrigin-RevId: f385bb8a9cdab1a6bfc28a8843b5128ceec364ec

server-ce/test/Jenkinsfile

@@ -48,7 +48,7 @@ pipeline {
       parallel {
         stage('Install deps') {
           steps {
-            sh 'make install'
+            sh 'make install -j10'
             sh 'make -C server-ce/test npm_install_in_docker'
             script { job_npm_install_done = true }
           }

services/web/frontend/js/features/source-editor/lezer-latex/README.md

@@ -38,7 +38,11 @@ The parser is written in a "grammar" file, (and a "tokens" file with custom toke
 
 From the monorepo root:
 
-``` sh
+```sh
+# automatic (on changes)
+make install
+
+# manually
 bin/npm -w services/web run 'lezer-latex:generate'
 ```