[csss-shadow-parts-1] Updates from tabatkins' review

- Use [=...=] and <dfn>
- Don't skip leading colons.
- Use / to denote pairs.
- error on trialing junk in mapping
- DOMToken -> token
- link pair and list

Author: fergald

css-shadow-parts-1/Overview.bs

@@ -324,36 +324,37 @@ Microsyntaxes for parsing {#parsing}
 Rules for parsing part mappings {#parsing-mapping}
 ----------------------------------------------
 
-A <span>valid part mapping</span> is a pair of DOMTokens
+A <dfn export>valid part mapping</dfn> is a [=pair=] of tokens
 separated by a U+003A COLON charater,
 with no other characters (e.g. no space characters).
-The DOMTokens must not contain U+003A COLON or U+002C COMMA characters.
+The tokens must not contain U+003A COLON or U+002C COMMA characters.
 
 The rules for parsing a part mapping are as follows:
 
 1. Let <var>input</var> be the string being parsed.
 
 1. Let <var>position</var> be a pointer into <var>input</var>, initially pointing at the start of the string.
 
-1. <span>Collect a sequence of code points</span> that are space characters or U+003A COLON characters.
-    This skips past any leading delimiters.
-1. <span>Collect a sequence of code points</span> that are not space characters or U+003A COLON characters,
+1. [=Collect a sequence of code points=] that are space characters
+1. [=Collect a sequence of code points=] that are not space characters or U+003A COLON characters,
     and let <var>first token</var> be the result.
 1. If <var>first token</var> is empty then return error.
-1. <span>Collect a sequence of code points</span> that are space characters.
-1. If the end of the <var>input</var> has been reached, return the pair <var>first token</var>, <var>first token</var>
+1. [=Collect a sequence of code points=] that are space characters.
+1. If the end of the <var>input</var> has been reached, return the [=pair=] <var>first token</var>/<var>first token</var>
 1. If character at <var>position</var> is not a U+003A COLON character, return error.
 1. Consume the U+003A COLON character.
-1. <span>Collect a sequence of code points</span> that are space characters.
-1. <span>Collect a sequence of code points</span> that are not space characters or U+003A COLON characters.
+1. [=Collect a sequence of code points=] that are space characters.
+1. [=Collect a sequence of code points=] that are not space characters or U+003A COLON characters.
     and let <var>second token</var> be the result.
 1. If <var>second token</var> is empty then return error.
-1. Return the pair <var>first token</var>, <var>second token</var>.
+1. [=Collect a sequence of code points=] that are space characters.
+1. If <var>position</var> is past the end of <var>input</var> then return error.
+1. Return the [=pair=] <var>first token</var>/<var>second token</var>.
 
 Rules for parsing a list of part mappings {#parsing-mapping-list}
 ----------------------------------------------
 
-A <span>valid list of part mappings</span> is a number of valid part mappings
+A <dfn export>valid list of part mappings</dfn> is a number of valid part mappings
 separated by a U+002C COMMA charater,
 with no other characters (e.g. no space characters).
 
@@ -363,15 +364,15 @@ The rules for parsing a list of part mappings are as follow:
 
 1. Let <var>position</var> be a pointer into <var>input</var>, initially pointing at the start of the string.
 
-1. Let <var>mappings</var> be an initially empty list of pairs of DOMTokens.
-    This list will be the result of this algorithm.
+1. Let <var>mappings</var> be an initially empty [=list=] of [=pairs=] of tokens.
+    This [=list=] will be the result of this algorithm.
 
-1. <span>Collect a sequence of code points</span> that are space characters, U+002C COMMA or U+003A COLON characters.
+1. [=Collect a sequence of code points=] that are space characters, U+002C COMMA.
     This skips past any leading delimiters.
 
 1. While <var>position</var> is not past the end of <var>input</var>:
 
-  1. <span>Collect a sequence of code points</span> that are not U+002C COMMA characters,
+  1. [=Collect a sequence of code points=] that are not U+002C COMMA characters,
       and let <var>unparsed mapping</var> be the result.
   1. Let <var>mapping</var> be the result of parsing <var>unparsed mapping</var> using the <span>rules for parsing part mappings</span>.
   1. If <var>mapping</var> is an error, continue.