We were rendering a Markdown link like `[Read file x.rs (lines
Y-Z)](@selection)` while the tool ran, but then switching to just `x.rs`
as soon as we got the file location from the tool call (due to an
if/else in the UI code that applies to all tools). This caused a
flicker, which is fixed by having `initial_title` return just the
filename from the input as it arrives instead of a link that we're going
to stop rendering almost immediately anyway.
Release Notes:
- N/A
Cole Miller
8c83281399