tint: IntrinsicTable: Rename open/closed -> template

The concept of 'closing' an open type or number made sense when these
were immutable once the first type/number had been matched during
overload resolution.
In order to support abstract numerics, these template parameters need to
be constrained as the arguments are evaluated, so there's no longer a
binary open / closed state.

Give up on this concept, and rename everything to 'template type' and
'template number'. This is likely easier for people to understand
anyway.

Also fix a small typo in the ICE message printed when there's an
ambiguous overload resolution (should never happen with the current
entries in the table).

Bug: tint:1504
Change-Id: I2bf043c71e5afa757259968eae4af830c50f38e0
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/90662
Commit-Queue: Ben Clayton <bclayton@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: David Neto <dneto@google.com>

tools/src/cmd/intrinsic-gen/sem/sem.go

@@ -30,10 +30,10 @@ type Sem struct {
 	UnaryOperators            []*Intrinsic
 	BinaryOperators           []*Intrinsic
 	ConstructorsAndConverters []*Intrinsic
-	// Maximum number of open-types used across all builtins
-	MaxOpenTypes int
-	// Maximum number of open-numbers used across all builtins
-	MaxOpenNumbers int
+	// Maximum number of template types used across all builtins
+	MaxTemplateTypes int
+	// Maximum number of template numbers used across all builtins
+	MaxTemplateNumbers int
 	// The alphabetically sorted list of unique parameter names
 	UniqueParameterNames []string
 }
@@ -137,8 +137,8 @@ type Overload struct {
 	Decl             ast.IntrinsicDecl
 	Intrinsic        *Intrinsic
 	TemplateParams   []TemplateParam
-	OpenTypes        []*TemplateTypeParam
-	OpenNumbers      []TemplateParam
+	TemplateTypes    []*TemplateTypeParam
+	TemplateNumbers  []TemplateParam
 	ReturnType       *FullyQualifiedName
 	Parameters       []Parameter
 	CanBeUsedInStage StageUses