docs: fix Duing typo in dev_notes build notes

[redstartechno]

What problem does this solve?

A typo in dev_notes/build.md — "Duing" should be "During" — in the build-issues note.

How do you know this is a real problem?

Line 4 reads Duing build, something like. "Duing" is a misspelling of "During"
(git grep Duing returns only this single occurrence).

How does this solve the problem?

Corrects the spelling Duing → During.

What risks does this introduce? How can we mitigate them?

None. Documentation-only change with no runtime behavior impact; single-word correction in one file.

How do you know this PR fixes the problem?

The word now reads "During". See the before/after diff below.

Which components are affected?

dev_notes/build.md only.

Testing & evidence

No code paths changed; automated tests are not applicable to this documentation-only change.

@@ Notes on build issues/fixes (line 4)
-Duing build, something like
+During build, something like

[redstartechno]

Closing in favor of #1306, which combines this and the other docs fixes into a single PR per the maintainer's request. Thanks!