Add else.project test

cabal-testsuite/PackageTests/ProjectImport/ParseErrorProvenance/cabal.out

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+# cabal v2-build
+Warning: <ROOT>/else.project, else.project: Unrecognized section '_' on line 3

cabal-testsuite/PackageTests/ProjectImport/ParseErrorProvenance/cabal.test.hs

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+import Test.Cabal.Prelude
+
+main = cabalTest . recordMode RecordMarked $ do
+  let log = recordHeader . pure
+
+  outElse <- fails $ cabal' "v2-build" [ "all", "--dry-run", "--project-file=else.project" ]
+  assertOutputContains
+    (normalizeWindowsOutput "When using configuration from: \
+    \  - else.project \
+    \  - dir-else/else.config")
+    outElse
+
+  return ()

cabal-testsuite/PackageTests/ProjectImport/ParseErrorProvenance/dir-else/else.config

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+if false
+else
+    _
+    packages: no-pkg-here

cabal-testsuite/PackageTests/ProjectImport/ParseErrorProvenance/else.project

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+import: dir-else/else.config