Refactor blob URL store definition

In the blob URL store definition, values are directly defined as blob URL
entries, but the keys definition is illogically split over two paragraphs. This
change fixes that (and fixes a minor capitalization error).

Author: Brian Drake

index.bs

@@ -1509,8 +1509,8 @@ All URLs are revoked when the global that created the URL itself goes away.
 
 Each user agent must maintain a <dfn id="BlobURLStore" export>blob URL store</dfn>.
 A [=blob URL store=] is a [=map=]
-where [=map/keys=] are [=valid URL strings=]
-and [=map/values=] are [=blob URL Entries=].
+where [=map/keys=] are [=blob URLs=]
+and [=map/values=] are [=blob URL entries=].
 
 A <dfn export>blob URL entry</dfn> consists of an <dfn for="blob URL entry">object</dfn> (of type
 {{Blob}} or {{MediaSource}}), and an <dfn export for="blob URL entry">environment</dfn> (an
@@ -1519,7 +1519,7 @@ A <dfn export>blob URL entry</dfn> consists of an <dfn for="blob URL entry">obje
 Note: Specifications have to use the [=obtain a blob object=] algorithm to access a
 [=blob URL entry=]'s [=blob URL entry/object=].
 
-[=map/Keys=] in the [=blob URL store=] (also known as <dfn lt="blob URL|object URL" export>blob URLs</dfn>)
+<dfn lt="blob URL|object URL" export>Blob URLs</dfn>
 are [=valid URL strings=] that when [=URL parser|parsed=]
 result in a [=/URL=] with a [=url/scheme=] equal to "`blob`",
 an [=empty host=], and a [=url/path=] consisting of one element itself also a [=valid URL string=].