sdk: generalize for any SDKs and enhance explanations (#8232)

* sdk: generalize for any SDKs and enhance explanations

1. There was a mix between 'gradle' and 'SDK'. We now only refer to 'SDK'.
Using the acronym for conciseness (the description explains the acronym).

2. Explanation for 'sdk use' was misleading. See https://sdkman.io/usage#use:

> It is important to realise that this will switch the candidate version for the current shell only.

3. Explanation for 'sdk current' has been enhanced, introducing the stable version concept aka 'candidate'.
See https://sdkman.io/usage#listcandidates:

> This will render a searchable alphabetic list with name, current stable default version (...)

* Update pages/common/sdk.md

Co-authored-by: marchersimon <50295997+marchersimon@users.noreply.github.com>

* Update pages/common/sdk.md

Co-authored-by: marchersimon <50295997+marchersimon@users.noreply.github.com>

* Update pages/common/sdk.md

Co-authored-by: marchersimon <50295997+marchersimon@users.noreply.github.com>

* Update pages/common/sdk.md

Co-authored-by: marchersimon <50295997+marchersimon@users.noreply.github.com>

* Update pages/common/sdk.md

Co-authored-by: marchersimon <50295997+marchersimon@users.noreply.github.com>

* Update pages/common/sdk.md

Co-authored-by: marchersimon <50295997+marchersimon@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: marchersimon <50295997+marchersimon@users.noreply.github.com>

Co-authored-by: marchersimon <50295997+marchersimon@users.noreply.github.com>

pages/common/sdk.md

@@ -4,34 +4,34 @@
 > Supports Java, Groovy, Scala, Kotlin, Gradle, Maven, Vert.x and many others.
 > More information: <https://sdkman.io/usage>.
 
-- Install a specific version of Gradle:
+- Install an SDK version:
 
-`sdk install {{gradle}} {{gradle_version}}`
+`sdk install {{sdk_name}} {{sdk_version}}`
 
-- Switch to a specific version of Gradle:
+- Use a specific SDK version for the current terminal session:
 
-`sdk use {{gradle}} {{gradle_version}}`
+`sdk use {{sdk_name}} {{sdk_version}}`
 
-- Check current Gradle version:
+- Show the stable version of any available SDK:
 
-`sdk current {{gradle}}`
+`sdk current {{sdk_name}}`
 
-- List all Software Development Kits available to install:
-
-`sdk list`
-
-- List all available versions for a specific Software Development Kit:
-
-`sdk list {{sdk_name}}`
-
-- List all installed Software Development Kits:
+- Show the stable versions of all installed SDKs:
 
 `sdk current`
 
-- Update Gradle to the latest version:
+- List all available SDKs:
 
-`sdk upgrade {{gradle}}`
+`sdk list`
 
-- Uninstall a particular version of Gradle:
+- List all versions of an SDK:
 
-`sdk rm {{gradle}} {{gradle_version}}`
+`sdk list {{sdk_name}}`
+
+- Upgrade an SDK to the latest stable version:
+
+`sdk upgrade {{sdk_name}}`
+
+- Uninstall a specific SDK version:
+
+`sdk rm {{sdk_name}} {{sdk_version}}`