Improve the look of wikis in search results

What does this MR do?

Previously we used to render these exactly the same as code results and only show a few lines of code. Since the wiki is more like human readable text then it makes more sense to just render it as text in paragraph form than lines of code. This also allows highlighting to pick up single words being matched.

Basically this is done by using the same styling we do on issue search results. It does come with the downside that we truncate the text so highlighting matching words later in the wiki won't be visible in the snippet anymore.

Screenshots (strongly suggested)

Before	After

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #260340 (closed)