git: openjdk/jdk: 8283648: Improve the snippet "file not found" message.

[Jonathan Gibbons]

Changeset: cb012a5b
Author:    Jonathan Gibbons <jjg at openjdk.org>
Date:      2022-03-25 21:20:02 +0000
URL:       https://git.openjdk.java.net/jdk/commit/cb012a5b625a7707c429f1e95db59018a6dcb992

8283648: Improve the snippet "file not found" message.

Reviewed-by: prappo

! src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/resources/doclets.properties
! src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/taglets/SnippetTaglet.java
! test/langtools/jdk/javadoc/doclet/testSnippetTag/TestSnippetTag.java