lint: Fix spelling errors in comments

[fyquah]

Found some spelling errors while running spelling linter #21245

This PR fixes them.

[practicalswift]

@fyquah

Luckily spelling errors cannot cause CI to fail, so the CI failure in the issue you referenced was not spelling related :)

With that said: Cnocept AKC on fiixng the speling erorrs! :)

FWIW this is the error that did cause the referenced CI failure:

This diff appears to have added new lines with trailing whitespace.
The following changes were suspected:

diff --git a/src/core_io.h b/src/core_io.h
@@ -22,0 +23,7 @@ class CTxUndo;
+
^---- failure generated from test/lint/lint-whitespace.sh

[hebasto]

With that said: Cnocept AKC on fiixng the speling erorrs! :)

:)

[fyquah]

diff --git a/src/core_io.h b/src/core_io.h
@@ -22,0 +23,7 @@ class CTxUndo;
+
^---- failure generated from test/lint/lint-whitespace.sh

Turns out I wasn't able to capture this because I was using a custom diff tool with git 🤔

[fanquake]

ACK fbbb2d4 - I thought we just fixed all of these.