fix check_ reference links to point to unified page

[jonathancallahan]

All of the check_slow~() and check_fast~() functions are now documented in a single documentation page. But the reference links in the built site (https://mazamascience.github.io/MazamaCoreUtils/reference/index.html) don't point to that page.

Also, the documentation you see inside RStudio when you type ?MazamaCoreUtils::check_fast is incorrect. The table summarizing functions has check_fastest() twice.

In this package, you will notice that related small functions can all be placed in the same .R file.

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This task is about learning how to create roxygen2 style documentation and how to use pkgdown::build_site() to create a documentation web site. I recommend approaching things in the following order:

• Read up on MazamaCoreUtils at https://mazamascience.github.io/MazamaCoreUtils/reference/index.html
• Identify all of the functions that have examples with grep "@example" R/*. Review the use of documentation comments and read up on roxygen2 to make sure you understand how to use them.
• Using the RStudio "Packages" tab, open up the documentation for each function with an example and try running them. All examples should begin with library(MazamaCoreUtils) and a carriage return so that they do not depend on any prior steps. Fix any examples that don't run properly.
• Fix the typo in the documentation in devtools_check.R.
• Run pkgdown::build_site() to see the web documentation.
• Read up on pkgdown links to figure out and fix the issue mentioned at the top.

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A couple of points on the documentation styling we’ve adopted:

• Package names should always be in bold so use ** in .Rmd files and \pkg{}` in roxygen2 comments.
• Function names should always be followed by () to make it easy to tell the difference between functions and variables.
• Variable names, character strings, etc. should often be in code font so use a backtick in .Rmd files and \code{} in roxygen2 comments.
• S4 classes should be in italics so use _ in .Rmd files and \emph{} in roxygen2 comments.