minor #5406 Update yaml_format.rst (marcel-burkhard)

This PR was submitted for the 2.7 branch but it was merged into the 2.3 branch instead (closes #5406).

Discussion
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Update yaml_format.rst

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | no

Commits
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366add9 Update yaml_format.rst

Author: wouterj

components/yaml/yaml_format.rst

@@ -223,7 +223,7 @@ YAML uses indentation with one or more spaces to describe nested collections:
       PHP:    5.2
       Propel: 1.3
 
-The following YAML is equivalent to the following PHP code:
+The above YAML is equivalent to the following PHP code:
 
 .. code-block:: php
 
@@ -240,7 +240,7 @@ The following YAML is equivalent to the following PHP code:
 
 There is one important thing you need to remember when using indentation in a
 YAML file: *Indentation must be done with one or more spaces, but never with
-tabulations*.
+tabulators*.
 
 You can nest sequences and mappings as you like: