doc: udpate list item spacing in changelogs

Minor formatting adjustments to two changelog files in preparation for a
markdown lint rule.

PR-URL: #24391
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>

doc/changelogs/CHANGELOG_V5.md

@@ -418,7 +418,7 @@ https://github.com/nodejs/node/pull/5655
 * **timers**: Internal Node.js timeouts now use the same logic path as those created with `setTimeout()` (Jeremiah Senkpiel) [#4007](https://github.com/nodejs/node/pull/4007)
   * This may cause a slightly different performance profile in some situations. So far, it has shown to be positive in most cases.
 * **v8**: backport fb4ccae from v8 upstream (Vladimir Krivosheev) #4231
-  -  breakout events from v8 to offer better support for external debuggers
+  - breakout events from v8 to offer better support for external debuggers
 * **zlib**: add support for concatenated members (Kári Tristan Helgason)
 https://github.com/nodejs/node/pull/5120
   * Previously, if multiple members were in the same archive, only the first would be read. The others are no longer thrown away.

doc/changelogs/CHANGELOG_V6.md

@@ -2167,16 +2167,16 @@ This LTS release comes with 168 commits. This includes 85 which are test related
 
 The SEMVER-MINOR changes include:
 
-*  **crypto**: allow adding extra certs to well-known CAs (Sam Roberts) [#9139](https://github.com/nodejs/node/pull/9139)
-*  **deps**: Upgrade INTL ICU to version 58 (Steven R. Loomis) [#9234](https://github.com/nodejs/node/pull/9234)
-*  **process**: add `process.memoryUsage.external` (Fedor Indutny) [#9587](https://github.com/nodejs/node/pull/9587)
-*  **src**: add wrapper for process.emitWarning() (Sam Roberts) [#9139](https://github.com/nodejs/node/pull/9139)
+* **crypto**: allow adding extra certs to well-known CAs (Sam Roberts) [#9139](https://github.com/nodejs/node/pull/9139)
+* **deps**: Upgrade INTL ICU to version 58 (Steven R. Loomis) [#9234](https://github.com/nodejs/node/pull/9234)
+* **process**: add `process.memoryUsage.external` (Fedor Indutny) [#9587](https://github.com/nodejs/node/pull/9587)
+* **src**: add wrapper for process.emitWarning() (Sam Roberts) [#9139](https://github.com/nodejs/node/pull/9139)
 
 
 Notable SEMVER-PATCH changes include:
 
-*  **fs**: cache non-symlinks in realpathSync. (Jeremy Yallop) [#10253](https://github.com/nodejs/node/pull/10253)
-*  **repl**: allow autocompletion for scoped packages (Evan Lucas) [#10296](https://github.com/nodejs/node/pull/10296)
+* **fs**: cache non-symlinks in realpathSync. (Jeremy Yallop) [#10253](https://github.com/nodejs/node/pull/10253)
+* **repl**: allow autocompletion for scoped packages (Evan Lucas) [#10296](https://github.com/nodejs/node/pull/10296)
 
 ### Commits