fix: avoid double searchPath call, use full path for editors on Windows

[Bhumika-SN]

Problem

Fixes #1340

On Windows with Git Bash, jbang edit finds IntelliJ's idea on
PATH correctly but then tries to execute just "idea" instead of
the full path like "idea.bat".

findEditorsOnPath() was calling searchPath() twice — once in
filter and once in map — which is inefficient.

Fix

Use a single map + filter to call searchPath() only once.
On Windows, return the full resolved path with extension so Git
Bash can execute it correctly.