Documentation: Make Headers Consistent in All MET Guides

[lisagoodrich]

This is a sub-issue of #898.
dtcenter/METplus#898

Describe the Sub-Issue

This task is for all METplus component. This specific issue is for MET only:

The headers for the MET components User's Guides may not be consistent, but we want them to be.

Here is the syntax from the RST docs (https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html#sections):

# with overline, for parts (e.g. the RTD documentation for the component (i.e. docs/index.rst), each guide (e.g. User's Guide, Contributor's Guide) (i.e. docs/Users_Guide/index.rst, docs/Contributors_Guide/index.rst))
* with overline, for chapters
=, for sections
-, for subsections
^, for subsubsections
", for paragraphs

Time Estimate

Estimate the amount of work required here.
Issues should represent approximately 1 to 3 days of work.

Define the Metadata

Assignee

• Select engineer(s) or no engineer required
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Milestone and Projects

• Select Milestone as the next official version or Backlog of Development Ideas
• For the next official version, select the MET-X.Y.Z Development project

Funding Source

2783543 - Lisa has hours on this account.