Document that YAML files are expected to be in YAML1.2 (#1764)

* Document that YAML files are expected to be in YAML1.2

Refer iterative/dvc#4415

* remove note, embed the note in the paragraph

* Apply suggestions from code review

Co-authored-by: Jorge Orpinel <jorgeorpinel@users.noreply.github.com>

* Restyled by prettier

Co-authored-by: Jorge Orpinel <jorgeorpinel@users.noreply.github.com>
Co-authored-by: Restyled.io <commits@restyled.io>

content/docs/command-reference/metrics/index.md

@@ -70,7 +70,7 @@ stages:
 
 ### Supported file formats
 
-Metrics can be organized as tree hierarchies in JSON or YAML files. DVC
+Metrics can be organized as tree hierarchies in JSON or YAML 1.2 files. DVC
 addresses specific metrics by the tree path. In the JSON example below, five
 metrics are presented: `train.accuracy`, `train.loss`, `train.TN`, `train.FP`
 and `time_real`.

content/docs/command-reference/params/index.md

@@ -24,7 +24,7 @@ dependencies: _parameters_. Parameters are defined using the the `-p`
 
 In contrast to a regular <abbr>dependency</abbr>, a parameter is not a file (or
 directory). Instead, it consists of a _parameter name_ (or key) to find inside a
-YAML, JSON, TOML, or Python _parameters file_. Multiple parameter dependencies
+YAML 1.2, JSON, TOML, or Python _parameters file_. Multiple parameter dependencies
 can be specified from one or more parameters files.
 
 The default parameters file name is `params.yaml`. Parameters should be

content/docs/command-reference/plots/index.md

@@ -50,9 +50,9 @@ differences between the metrics in different experiments.
 
 ### Supported file formats
 
-Plot metrics can be organized as data series in JSON, YAML, CSV, or TSV files.
-DVC expects to see an array (or multiple arrays) of objects (usually _float
-numbers_) in the file.
+Plot metrics can be organized as data series in JSON, YAML 1.2, CSV, or TSV
+files. DVC expects to see an array (or multiple arrays) of objects (usually
+_float numbers_) in the file.
 
 In tabular file formats such as CSV and TSV, each column is an array.
 `dvc plots` subcommands can produce plots for a specified column or a set of

content/docs/user-guide/dvc-files-and-directories.md

@@ -16,7 +16,7 @@ Additionally, there are a few metafiles that support DVC's features:
   These typically have a matching `dvc.lock` file to record the pipeline state
   and track its <abbr>data artifacts</abbr>.
 
-Both `.dvc` files and `dvc.yaml` use human-friendly YAML schemas, described
+Both `.dvc` files and `dvc.yaml` use human-friendly YAML 1.2 schemas, described
 below. We encourage you to get familiar with them so you may create, generate,
 and edit them on your own.