feat: TechDocs - Add vale linter to check words quality in md files. (#2631)

* fix(docs): typos which were reflacted from vale linter's command

* feat: Implement Vale linter (#2031)
Initialize .vale.ini file
Add 'lint:docs' script to package.json, to lint all md files except the ones which are located in node_modules
Generate 'vocab.txt' by using command 'yarn run lint:docs' | grep -o ''[a-z A-Z]*'' | grep -o '[a-z A-Z]*' | sort | uniq > .github/styles/vocab.txt
Add steps to github workflow 'master' to check docs quality

* chore: Separate workflow for quality checking

* chore: Added 'shx' dev dependency to support grep command in cross platform

* feat: Add script to operate same quality check process on different platform

* ignore: remove lint:docs from lint-stages which was added for experiment purpose

* fix: check-all-files on push event & check-changed-files on pull_request event

* chore(CI): triggle workflow only when there is any updates in .md file(s) on pull request

* fix: use spawnSync to solve 'The command line is too long.' error

* fix: github workflow syntax

* fix: prettier error

* chore: add vale command directly to lint-staged

* chore: use shebang for easy access

* fix: windows script issue & remove shebang

* chore: Add shebang flag

* chore: better error message related to vale

* chore: mention vale linter in documentation

* fix: spelling errors & add keywords to vocab.txt

plugins/api-docs/README.md

@@ -18,7 +18,7 @@ Right now, the following API formats are supported:
 - [AsyncAPI](https://www.asyncapi.com/docs/specifications/latest/)
 - [GraphQL](https://graphql.org/learn/schema/)
 
-Other formats are displayed as plain text, but this can easily be extented.
+Other formats are displayed as plain text, but this can easily be extended.
 
 To fill the catalog with APIs, [provide entities of kind API](https://backstage.io/docs/features/software-catalog/descriptor-format#kind-api).
 To link that an component implements an API, see [`implementsApis` property on components](https://backstage.io/docs/features/software-catalog/descriptor-format#specimplementsapis-optional).