docs(migration): add slash for Express named wildcard

[sjoerdsmink]

Add slash for Express route matching syntax

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PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Docs
• Other... Please describe:

What is the current behavior?

Incorrect mentioning of {*splat} that it is a named wildcard that matches any path including the root path. It actually does not include the root path. See the Express migration docs

Issue Number: N/A

What is the new behavior?

Adding a slash in the example, and mentioning that it doesn't include the root path.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[kamilmysliwiec]

/ shouldn't be required IIRC

[sjoerdsmink]

@kamilmysliwiec It's mentioned explicitly in the docs, in the note

*splat matches any path without the root path. If you need to match the root path as well /, you can use /{*splat}, wrapping the wildcard in braces.

[kamilmysliwiec]

Nest adds / automatically though

[sjoerdsmink]

Ok, I didn't know that, thanks. forRoutes seems to work without the slash as well.