fix: Correct flake8 config

- Add exclude pattern for flake8 when running with pre-commit as it does
  not fully honor the exclude paths.
- Cleanup exclude paths for flake8 in tox.ini
- Re-enable line length check and correct three affected files

qt/exclude_list_dialog.py

@@ -165,8 +165,8 @@ Directores will also have their <strong>default state</strong> set to Excluded \
 in the Directories tab if their name happens to match one of the selected regular expressions.<br>\
 For each file collected, two tests are performed to determine whether or not to completely ignore it:<br>\
 <li>1. Regular expressions with no path separator in them will be compared to the file name only.</li>
-<li>2. Regular expressions with at least one path separator in them will be compared to the full path to the file.</li><br>
-Example: if you want to filter out .PNG files from the "My Pictures" directory only:<br>\
+<li>2. Regular expressions with at least one path separator in them will be compared to the full path to the file.</li>\
+<br>Example: if you want to filter out .PNG files from the "My Pictures" directory only:<br>\
 <code>.*My\\sPictures\\\\.*\\.png</code><br><br>\
 You can test the regular expression with the "test string" button after pasting a fake path in the test field:<br>\
 <code>C:\\\\User\\My Pictures\\test.png</code><br><br>

qt/preferences_dialog.py

@@ -146,7 +146,8 @@ On MacOS, the tab bar will fill up the window's width instead."
         )
         self.use_native_dialogs.setToolTip(
             tr(
-                "For actions such as file/folder selection use the OS native dialogs.\nSome native dialogs have limited functionality."
+                "For actions such as file/folder selection use the OS native dialogs.\n\
+Some native dialogs have limited functionality."
             )
         )
         layout.addWidget(self.use_native_dialogs)
@@ -217,7 +218,8 @@ use the modifier key to drag the floating window around"
     def _setup_advanced_page(self):
         tab_label = QLabel(
             tr(
-                "These options are for advanced users or for very specific situations, most users should not have to modify these."
+                "These options are for advanced users or for very specific situations, \
+most users should not have to modify these."
             ),
             wordWrap=True,
         )