welcome to our community! You raised a very valuable comment and we just took it into consideration to improve our documentation (please check this PR).
On a side note, SONARQUBE_WEB_JVM_OPTS is an old environment variable and got replaced by SONAR_WEB_JAVAOPTS (the same happened to SONARQUBE_CE_JVM_OPTS with SONAR_CE_JAVAOPTS).
Please let us know if that’s clearer now, do not hesitate to contact us back if that’s not the case.