procedural-masquerade doc typos

Auto merge of servo#200 - servo:location-in-errors, r=SimonSapin

Include a SourceLocation in all error types

This is part of https://bugzilla.mozilla.org/show_bug.cgi?id=1378861

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Auto merge of servo#199 - upsuper:nth-boundary, r=emilio

Avoid boundary check in parse_n_dash_digits

Fix [bug 1404678](https://bugzilla.mozilla.org/show_bug.cgi?id=1404678).

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Auto merge of servo#197 - tromey:remember-source-url, r=SimonSapin

Preserve sourceURL comment in parser

In addition to the sourceMappingURL comment, there is a second special
comment, "sourceURL", that can be used to set the "display name" of a
style sheet for developer tools.  This name is also used as the base
URL for the source-map URL resolution algorithm.  sourceURL is
described here:
https://blog.getfirebug.com/2009/08/11/give-your-eval-a-name-with-sourceurl/
The relevant Firefox bug is here:
https://bugzilla.mozilla.org/show_bug.cgi?id=880831

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Auto merge of servo#196 - tromey:one-based-columns, r=SimonSapin

Report columns as 1-based

Change cssparser to report columns as being 1-based, for Gecko
compatibility.  Formerly this offsetting was handled in Servo, but it
wasn't done on all code paths, so we agreed to put it into
rust-cssparser.  For some background, see:
https://bugzilla.mozilla.org/show_bug.cgi?id=1398869

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Auto merge of servo#194 - servo:bad, r=emilio

Fix serialization of bad-string and bad-url tokens

This will help fix https://bugzilla.mozilla.org/show_bug.cgi?id=1396664.

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Auto merge of servo#180 - upsuper:at-rule-parser, r=SimonSapin

Have at-rule without block handled in two stages as well

This change makes `AtRuleParser::parse_prelude` always return a prelude if parsed successfully, so that at-rules which do not accept block can be handled in two phases just like those with block.

This is important because at-rules without block usually have side effects. If `parse_prelude` executes the side effect, but `parse_at_rule` later determined that the rule is actually invalid (e.g. because it is followed by a block), there is no way for impl of `AtRuleParser` to undo the side effect.

It provides the necessary parser side change for fixing [Gecko bug 1388911](https://bugzilla.mozilla.org/show_bug.cgi?id=1388911).

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Auto merge of servo#186 - servo:smolvec, r=emilio

Use a SmallVec instead of Vec in consume_until_end_of_block

… to avoid allocating in common cases.

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Auto merge of servo#181 - servo:skip_whitespace, r=nox

Add Parser::skip_whitespace

(and use it it rule parsing to make it hopefully more efficient.)

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