[Docs] New section to modifier docs: Checking Modifier State (#10550)

* Added new section to docs: Checking Modifier State

* Added id anchors to all headers in modifiers docs

* Added a Wikipedia link to bitwise operators and...

crosslinked to the QMK macro docs.

* Added an explanation on the format of mod bitmask

* Added .md extension to hyperlinks to macros docs

* Corrected mod mask order and changed notation

* Documented add_oneshot_mods and del_oneshot_mods

* Mentioned modifier checks in the macro docs

* Explained strict modifier checking

i.e. using `get_mods() & MOD_MASK == MOD_MASK` instead of simply
`get_mods() & MOD_MASK`

* Added (un)register_mods to the docs

* Put left term of comparison in parens

1 files changed, 1 insertions, 1 deletions

diff --git a/docs/feature_macros.md b/docs/feature_macros.md
index 6e69ad642c..3660f37755 100644
--- a/docs/feature_macros.md
+++ b/docs/feature_macros.md
@@ -209,7 +209,7 @@ SEND_STRING(".."SS_TAP(X_END));
 
 There are some functions you may find useful in macro-writing. Keep in mind that while you can write some fairly advanced code within a macro, if your functionality gets too complex you may want to define a custom keycode instead. Macros are meant to be simple.
 
-?> You can also use the functions described in [Useful functions](ref_functions.md) for additional functionality. For example `reset_keyboard()` allows you to reset the keyboard as part of a macro.
+?> You can also use the functions described in [Useful function](ref_functions.md) and [Checking modifier state](feature_advanced_keycodes#checking-modifier-state) for additional functionality. For example, `reset_keyboard()` allows you to reset the keyboard as part of a macro and `get_mods() & MOD_MASK_SHIFT` lets you check for the existence of active shift modifiers.
 
 ### `record->event.pressed`