docs: Fix broken links in markdown documentation

Signed-off-by: bo.jiang <bo.jiang@daocloud.io>

ADOPTERS.md

@@ -10,7 +10,7 @@ A non-exhaustive list of k3s adopters is provided below.  To add your company to
 - [Child Rescue Coalition](https://www.childrescuecoalition.org)
 
 **_Other Projects_** - While the above list provides a number of official adopters, k3s' compact and simple nature provides a clean base for other projects to build off of, or to embed.  Some such projects are listed below:
- - SUSE's RKE2 (or RKE Government) [RKE2](github.com/rancher/rke2/)
+ - SUSE's RKE2 (or RKE Government) [RKE2](https://github.com/rancher/rke2/)
  - [k3ai](https://k3ai.github.io/)
  - SUSE's [Rancher Desktop](https://rancherdesktop.io/)
  - [Kairos](https://kairos.io)

README.md

@@ -105,7 +105,7 @@ Community
 ---
 - ### Slack
 
-Join [Slack](https://slack.rancher.io/) to chat with K3s developers and other K3s users. Great place to learn and ask questions: [#k3s](https://rancher-users.slack.com/archives/CGGQEHPPW) and [#k3s-contributor](https://rancher-users.slack.com/archives/CGXR87T8B) and [#k3s](https://cloud-native.slack.com/archives/C0196ULKX8S) channel in [CNCF Slack](cloud-native.slack.com)
+Join [Slack](https://slack.rancher.io/) to chat with K3s developers and other K3s users. Great place to learn and ask questions: [#k3s](https://rancher-users.slack.com/archives/CGGQEHPPW) and [#k3s-contributor](https://rancher-users.slack.com/archives/CGXR87T8B) and [#k3s](https://cloud-native.slack.com/archives/C0196ULKX8S) channel in [CNCF Slack](https://cloud-native.slack.com)
 
 - ### Getting involved
 [GitHub Issues](https://github.com/k3s-io/k3s/issues) - Submit your issues and feature requests via GitHub.

tests/TESTING.md

@@ -4,8 +4,8 @@ Testing in K3s comes in 5 forms:
 - [Unit](#unit-tests)
 - [Integration](#integration-tests)
 - [Docker](#docker-tests)
-- [Smoke](#smoke-tests)
-- [Performance](#performance)
+- [Install](#install-tests)
+- [Performance](#performance-tests)
 - [End-to-End (E2E)](#end-to-end-e2e-tests)
 - [Distros-test-framework](#distros-test-framework)
 
@@ -68,10 +68,10 @@ ___
 
 ## Install Tests
 
-Install tests are a collection of tests defined under the [tests/install](./tests/install). These tests are used to validate the installation and operation of K3s on a variety of operating systems. The test themselves are Vagrantfiles describing single-node installations that are easily spun up with Vagrant for the `libvirt` and `virtualbox` providers:
+Install tests are a collection of tests defined under the [tests/install](./install). These tests are used to validate the installation and operation of K3s on a variety of operating systems. The test themselves are Vagrantfiles describing single-node installations that are easily spun up with Vagrant for the `libvirt` and `virtualbox` providers:
 
 - [Install Script](install) :arrow_right: scheduled nightly and on an install script change
-  - [CentOS 9 Stream](install/centos-stream)
+  - [CentOS 9 Stream](install/centos-9)
   - [Rocky Linux 8](install/rocky-8) (stand-in for RHEL 8)
   - [Rocky Linux 9](install/rocky-9) (stand-in for RHEL 9)
   - [Fedora 40](install/fedora)

tests/e2e/README.md

@@ -18,7 +18,7 @@ A E2E test consists of two parts:
 1. `Vagrantfile`: a vagrant file which describes and configures the VMs upon which the cluster and test will run
 2. `<TEST_NAME>.go`: A go test file which calls `vagrant up` and controls the actual testing of the cluster
 
-See the [validate cluster test](../tests/e2e/validatecluster/validatecluster_test.go) as an example.
+See the [validate cluster test](./validatecluster/validatecluster_test.go) as an example.
 
 
 ## Setup