Adjust how `slang` and `slangc` uses a `profile` to manage the stage of an entry-point (#4670)

* Fixes #4656

Changes:
1. Setting a profile via slangc no-longer sets an entry-point target-stage, this is to allow slangc to follow how the SLANG-API works (else `main` is assumed to be the default entry-point)
2. If the stage specified by a profile is not equal to the stage specified by a entry-point, we throw a capability error.
3. Resolving the stage of an entry point was changed to function (mostly) equally for when 0 entry-points are specified versus to when there are 1 or more.
4. changed capabilitySet Iterator so it is invalid if backing data is nullptr (although this should never happen, it would stop crashes in the worst case).

* remove the breaking change since it likely is going to be a lot more than just a simple change due to the implicit `main` and stage through `profile` code.

* print out profile name with errors

* use target's profile for printing

* change logic to print warning in a different method (account for more cases)

* set unknown stages

1 files changed, 1 insertions, 1 deletions

diff --git a/source/slang/slang-check-decl.cpp b/source/slang/slang-check-decl.cpp
index 28d1ae02e..99aecd37c 100644
--- a/source/slang/slang-check-decl.cpp
+++ b/source/slang/slang-check-decl.cpp
@@ -10489,7 +10489,7 @@ namespace Slang
                 auto stageCaps = CapabilitySet(Profile(entryPointAttr->stage).getCapabilityName());
                 if (declaredCaps.isIncompatibleWith(stageCaps))
                 {
-                    maybeDiagnose(getSink(), this->getOptionSet(), DiagnosticCategory::Capability, funcDecl->loc, Diagnostics::stageIsInCompatibleWithCapabilityDefinition, funcDecl, stageCaps, declaredCaps);
+                    maybeDiagnose(getSink(), this->getOptionSet(), DiagnosticCategory::Capability, funcDecl->loc, Diagnostics::stageIsIncompatibleWithCapabilityDefinition, funcDecl, stageCaps, declaredCaps);
                 }
                 else
                 {