add missing pr links

Author: Bahex

blog/2025-10-14-nushell_v0_108_0.md

@@ -839,7 +839,7 @@ http get --allow-errors https://api.example.com/events.jsonl
 
 ### Breaking changes
 
-### `collect` removes `source` metadata (TODO)
+### `collect` removes `source` metadata ([#16821])
 
 `collect` now removes `source` metadata field even when `content_type` is set.
 Previously: both were preserved, now only `content_type` is preserved.
@@ -979,10 +979,10 @@ Module path completion for command `use`/`source` now behaviors in the same mann
 
 Fixed the bug of empty result of external executable path completion at the head of a pipeline when the path prefix contains spaces.
 
-### boolean coloring in light theme (TODO)
+### boolean coloring in light theme ([#16722])
 When using `std/config light-theme`, booleans inside structures are now colored in dark cyan instead of white, which was very hard to read in combination with a light terminal background.
 
-### changed fallback for unknown color names (TODO)
+### changed fallback for unknown color names ([#16722])
 If some named color in `$env.config.color_config` is misspelled or otherwise unknown to nu, the corresponding element is now colored using the terminal's default (as in `ansi reset`) instead of white.
 
 ### Improve collection type inference ([#16530])