Add RTX, flamegraphs, winget to spelling allow list

These terms were introduced by the recent GitHub issue template
modernization and are flagged by the check-spelling CI job.

Signed-off-by: Christian Parpart <christian@parpart.family>

Author: christianparpart

.github/actions/spelling/allow/allow.txt

@@ -12,6 +12,7 @@ FreeBSD
 LASTEXITCODE
 OPENCONSOLE
 OpenBSD
+RTX
 SEMA
 STARTCHAR
 STARTFONT
@@ -32,6 +33,7 @@ copy'n'paste
 copyable
 crossfade
 dbus
+flamegraphs
 gha
 ilammy
 lazygit
@@ -55,4 +57,5 @@ tparam
 unk
 urg
 vswhere
+winget
 zypper