revise runner architecture tags (team#40780)

service/ci.md

@@ -418,8 +418,10 @@ Whether a runner will pick a job depends on a few things:
 We currently use the following tags:
 
  * **architecture**:
-   * `amd64`: popular [64-bit Intel/AMD architecture](https://en.wikipedia.org/wiki/X86-64)
-   * `aarch64`: the [64-bit ARM extension](https://en.wikipedia.org/wiki/AArch64)
+   * `amd64`: popular [64-bit Intel/AMD architecture](https://en.wikipedia.org/wiki/X86-64) (equivalents: `x86_64` and `x86-64`)
+   * `aarch64`: the [64-bit ARM extension](https://en.wikipedia.org/wiki/AArch64) (equivalents: `arm64` and `arm64-v8a`)
+   * `ppc64le`: [IBM Power architecture](https://en.wikipedia.org/wiki/Ppc64)
+   * `s390x`: [Linux on IBM Z architecture](https://en.wikipedia.org/wiki/Linux_on_IBM_Z)
  * **OS**: `linux` is usually implicit but other tags might eventually
    be added for other OS
  * **executor** type: `docker`, `KVM`, etc. `docker` are the typical
@@ -429,7 +431,7 @@ We currently use the following tags:
  * **hosting** provider:
    * `TPA`: runners managed by the sysadmin team
    * `fdroid`: provided as a courtesy by the [F-Droid project](https://f-droid.org/)
-   * `OSUOSL`: runners provided by the [OSUOSL](https://osuosl.org/)
+   * `osuosl`: runners provided by the [OSUOSL](https://osuosl.org/)
  * **features**:
    * `privileged`: those containers have actual root access and should
      explicitly be able to run `DinD`