Fix apply statement parsing and ABNF (#1414)

This fixes an issue where `applySomeShape @someTrait` was valid,
without any space between the apply and shape name. The fix makes
it so spacing is required, not line breaks as was the case in
the old ABNF, to be consistent with other shapes grammar
(see [SimpleShapeStatement](https://awslabs.github.io/smithy/2.0/spec/idl.html#grammar-token-smithy-SimpleShapeStatement))

docs/source-1.0/spec/core/idl.rst

@@ -235,7 +235,7 @@ string support defined in `RFC 5234 <https://www.rfc-editor.org/rfc/rfc7405>`_.
                             :      *(`Comma` `TraitStructureKvp` *`WS`)
                             :  `TrailingComma`
     TraitStructureKvp       :`NodeObjectKey` *`WS` ":" *`WS` `NodeValue`
-    ApplyStatement          :%s"apply" `WS` `ShapeId` `WS` `Trait` `BR`
+    ApplyStatement          :%s"apply" `SP` `ShapeId` `WS` `Trait` `BR`
 
 .. rubric:: Shape ID
 

docs/source-2.0/spec/idl.rst

@@ -237,7 +237,7 @@ string support defined in `RFC 5234 <https://www.rfc-editor.org/rfc/rfc7405>`_.
     TraitStructure          :`TraitStructureKvp` *(*`WS` `TraitStructureKvp`)
     TraitStructureKvp       :`NodeObjectKey` *`WS` ":" *`WS` `NodeValue`
     ApplyStatement          :(`ApplyStatementSingular` / `ApplyStatementBlock`)
-    ApplyStatementSingular  :%s"apply" `WS` `ShapeId` `WS` `Trait` `BR`
+    ApplyStatementSingular  :%s"apply" `SP` `ShapeId` `WS` `Trait` `BR`
     ApplyStatementBlock     :%s"apply" `SP` `ShapeId` `WS` "{" `TraitStatements` "}" `BR`
 
 .. rubric:: Shape ID

smithy-model/src/main/java/software/amazon/smithy/model/loader/IdlModelParser.java

@@ -1126,7 +1126,7 @@ private void parseApplyStatement() {
         expect('p');
         expect('l');
         expect('y');
-        sp();
+        rsp();
 
         String name = ParserUtils.parseShapeId(this);
         rws();