Scaladoc: Some functions not shown in scaladoc searchbar

## Compiler version

Nightly

## Minimized example

1. Open https://dotty.epfl.ch/api/index.html
2. Open scaladoc searchbar
3. Search for `asExpr`

## Output

Nothing

## Expectation

`asExpr` in trait `TreeMethods`.
https://dotty.epfl.ch/api/scala/quoted/Quotes$reflectModule$TreeMethods.html#asExpr-d00
