Fix docs (#1035)

Co-authored-by: Anbraten <anton@ju60.de>

docs/docs/20-usage/20-pipeline-syntax.md

@@ -332,12 +332,12 @@ when:
   event: tag
 ```
 
-Execute a step if the build event is a `tag` created from the specified branch:
+Execute a step if the pipeline event is a `push` to a specified branch:
 
 ```diff
 when:
-  event: tag
-+ branch: master
+  event: push
++ branch: main
 ```
 
 Execute a step for all non-pull request events:

docs/docs/20-usage/35-advanced-yaml-syntax.md

@@ -9,10 +9,10 @@ To convert this:
 pipeline:
   test:
     image: golang:1.18
-    command: go test ./...
+    commands: go test ./...
   build:
     image: golang:1.18
-    command: build
+    commands: build
 ```
 
 Just add a new section called **variables** like this:
@@ -25,11 +25,11 @@ Just add a new section called **variables** like this:
    test:
 -    image: golang:1.18
 +    image: *golang_image
-     command: go test ./...
+     commands: go test ./...
    build:
 -    image: golang:1.18
 +    image: *golang_image
-     command: build
+     commands: build
 ```
 
 ## Example of YAML override and extension