docs: fix ellipsis in code-snippet in creating-libraries guide (angular#45820)

When hard-coding content in a `<code-example>` tag inside an `.md` file,
the content is treated as HTML by the Markdown processor and thus any
characters with special meaning in HTML have to be encoded (or replaced
with HTML entities).

However, the content that is embedded into `<code-example>` tags via
docregions is treated as text (since it is not parsed by the Markdown
processor) and thus should not have encoded characters or HTML entities.

PR Close angular#45820

Author: gkalpak

aio/content/examples/angular-linker-plugin/webpack.config.mjs

@@ -1,4 +1,4 @@
-// #docplaster …
+// #docplaster ...
 // #docregion webpack-config
 import linkerPlugin from '@angular/compiler-cli/linker/babel';