Make Compilation mode recognize non-legacy Kotlin/Gradle errors

Make Compilation mode recognize non-legacy Kotlin/Gradle errors

The Compilation mode recognizes Kotlin/Gradle errors but only in
the now legacy format.  The current format, which has been in wide
use for about a year, is not supported.  This change adds support
for the current format.
* etc/compilation.txt: (symbols): Add examples of non-legacy
Kotlin/Gradle warnings and errors.
* lisp/progmodes/compile.el: (compilation-error-regexp-alist-alist):
Rename 'gradle-kotlin' to 'gradle-kotlin-legacy' and add
'grade-kotlin' that matches the errors and warnings outputted by
the current (non-legacy) Kotlin/Gradle.  (Bug#70797)
* test/lisp/progmodes/compile-tests.el
(compile-tests--test-regexps-data): Rename 'gradle-kotlin' to
'gradle-kotlin-legacy' and add two test cases for the newly added,
non-legacy Kotlin/Gradle warnings and errors.