minor symfony#8019 Minor reword of the intro of the routing/conditions article (javiereguiluz)

This PR was merged into the 2.7 branch.

Discussion
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Minor reword of the intro of the routing/conditions article

Two changes:

* Starting with "As you've seen..." is wrong because each article should be self-contained.
* "wildcards" is not OK because in other docs we mostly use "placeholders"

Commits
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5bda060 Minor reword of the intro of the routing/conditions article

Author: weaverryan

routing/conditions.rst

@@ -4,9 +4,9 @@
 How to Restrict Route Matching through Conditions
 =================================================
 
-As you've seen, a route can be made to match only certain routing wildcards
-(via regular expressions), HTTP methods, or host names. But the routing system
-can be extended to have an almost infinite flexibility using ``conditions``:
+A route can be made to match only certain routing placeholders (via regular
+expressions), HTTP methods, or host names. If you need more flexibility to
+define arbitrary matching logic, use the ``conditions`` routing option:
 
 .. configuration-block::