Package directories in inspector settings should end with a slash

[Elliott Brooks]

For example:

/Users/elliottbrooks/dev/devtools/packages/devtools_app/

not

/Users/elliottbrooks/dev/devtools/packages/devtools_app

Currently we are missing the ending slash, and so are matching packages that begin the same way, e.g. /Users/elliottbrooks/dev/devtools/packages/devtools_app_shared