docs: code comments name the headings README has now (closes #724)

The README rewrite renamed or merged several headings that comments still
cited. Each comment now names the current heading. Line number citations of
README become headings too, and one test name drops its line numbers.

The e2e workflow's citations of "In CI" are dropped, because no section has what
they pointed at. Its comment also corrects what it says about required jobs and
open reports.

The comment on withLock() no longer states a Firefox private window exception,
because the manifest keeps the extension out of those windows.

Two comments also take corrections from reviews: the cases with no total in
DeleteAddress's warning, and the screens that say a swap's amount could not be
decoded.

Model: opus-5-5

src/popup/views/deleteAddress.js

@@ -83,10 +83,11 @@ function recoveryPathText(wallet) {
 // rounded number would report "0.0000 ETH" for an address holding real money.
 // The lines below it carry the amounts, in the same format as Home and
 // AddressDetail, followed by the USD total when there is one to give — no
-// total line at all on testnet or before the first price fetch, and no figure
-// when every holding here is one with no price, since "$0.00" directly under
-// "This address holds a balance." is a contradiction. A token holding below
-// 0.000001 does not count, as the lines below leave it out.
+// total line at all on testnet, before the first price fetch or while no
+// refresh has read the ETH balance, and no figure when every holding here is
+// one with no price, since "$0.00" directly under "This address holds a
+// balance." is a contradiction. A token holding below 0.000001 does not count,
+// as the lines below leave it out.
 //
 // While no refresh has read the ETH balance the address may be empty, so the
 // sentence says "may hold".