XWIKI-19288: Plain Text Mentions 1.0 syntax doesn't have a nice friendly name

...platform-mentions/xwiki-platform-mentions-default/pom.xml

...i/mentions/internal/rendering/MentionsSyntaxProvider.java

...ns/internal/rendering/PlainTextMentionsBlockRenderer.java

...entions/internal/rendering/PlainTextMentionsRenderer.java

.../internal/rendering/PlainTextMentionsRendererFactory.java

...ntions-default/src/main/resources/META-INF/components.txt

...ntions/internal/rendering/MentionsSyntaxProviderTest.java