Remove bracket rotations in favor of <x, y, z>. Addresses #757. (#888)

* Only allow <x, y, z> rotations. Addresses #757.

Based on feedback, removing more than this may be beneficial, but some competitors strongly prefer to keep them. However, reducing to a single rotation sytem is generally supported, and the community prefers <x, y, z> over bracket rotations.

* Update wca-regulations.md

Co-Authored-By: Iván Brigidano Pérez <47502355+Ivan-Brigidano@users.noreply.github.com>

* Update wca-regulations.md

Co-Authored-By: Iván Brigidano Pérez <47502355+Ivan-Brigidano@users.noreply.github.com>

* Update wca-regulations.md

Co-Authored-By: Iván Brigidano Pérez <47502355+Ivan-Brigidano@users.noreply.github.com>

* Update wca-regulations.md

* Update wca-guidelines.md

* Update wca-guidelines.md

Co-Authored-By: Han Wu <3752812+hanwu85@users.noreply.github.com>

wca-guidelines.md

@@ -213,9 +213,9 @@ To be more informative, each Guideline is classified using one of the following
 - E2c1+++) [EXPLANATION] The competitor is not required to write the competition name, round, and/or attempt number on their submitted paper, but may wish to do so in order to help the organization team keep track of submitted solutions.
 - E2c1++++) [ADDITION] If a judge finds a submitted solution without information to identify the attempt (e.g. while grading the attempt), they should find out the competitor who wrote the solution in order to assign them a DNF (rather than DNS). Note that the competitor must not be allowed to write information to identify the attempt at this point, so they must receive a DNF result.
 - E2c2+) [EXAMPLE] Examples that are not considered a single unambiguous move sequence: multiple solution sequences without exactly one clearly indicated solution, a solution with ambiguous symbols (e.g. a letter that looks similar to "B" and "R" but is not clearly one or the other), a solution with stars or arrows indicating moves to be performed out of written order (e.g. "insertions" that are not written in-line with the rest of the move sequence, "pre-moves" that are not incorporated into the move sequence using valid notation), a move sequence that is not written out roughly as a series of lines in reading order, any arrangement of symbols that cannot be interpreted as an unambiguous move sequence. Exceptions to the examples above: small typographic corrections (e.g. blacking out moves and writing moves above that are clearly meant to replace them, moves written in subscript or superscript to fit between other moves).
-- E2c2++) [ADDITION] If a competitor uses the incorrect type of brackets/parentheses to write a rotation due to inexperience, the judge may interpret the competitor's intention as the correct brackets (and the competitor should be informed), at the discretion of the WCA Delegate. Example: {r}, <r>, or (r) may be interpreted as [r]. Note that only the bracket type may reinterpreted in this way, and notation such as or [R], [r u], or [r]2 is still considered invalid (see [Guideline E2c4+](guidelines:guideline:E2c4+)).
+- E2c2++) [REMINDER] In the past, bracket notations (e.g. [r] or [u2]) were permitted for Fewest Moves. Only rotations based on x, y, or z are permitted now (see [Regulation 12a4a](regulations:regulation:12a4a)).
 - E2c3+) [CLARIFICATION] If a move is not clearly blacked out/scribbled out and it is not clear whether the move is part of the solution, the judge should consider it an ambiguous move sequence (see [Regulation E2c2](regulations:regulation:E2c2) and [Guideline E2c2+](guidelines:guideline:E2c2+)).
-- E2c4+) [CLARIFICATION] Examples of symbols or combinations of symbols that are not permitted in solutions for 3x3x3 Fewest Moves: M, e, r, Y (uppercase), T, U1, Ui, U3, U-, R++, R2', R'2, L'w, 1R, 2U, 2f, 2-3r, 1Rw, 3Rw, 2-3Rw, rw, Rr, *, →, ⮐, /, ., ?, [r u], [F], <f>, [f]', [f]2, [x], (x), (L), 2(Rw), (U)2, (U)', (R U)', (R U R'), [R, U], [R: U].
+- E2c4+) [CLARIFICATION] Examples of symbols or combinations of symbols that are not permitted in solutions for 3x3x3 Fewest Moves: M, e, r, Y (uppercase), T, U1, Ui, U3, U-, R++, R2', R'2, L'w, 1R, 2U, 2f, 2-3r, 1Rw, 3Rw, 2-3Rw, rw, Rr, *, →, ⮐, /, ., ?, [r], [r u], [F], <f>, [f]', [f]2, [x], (x), (L), 2(Rw), (U)2, (U)', (R U)', (R U R'), [R, U], [R: U].
 - E2e+) [CLARIFICATION] Competitors must not derive solutions from any part of the scramble sequence, and solutions should not share significant parts with the inverse scramble sequence.
 - E2e++) [EXAMPLE] Example of solutions that should result in a disqualification of the attempt (DNF): solutions beginning with the same 4 or more moves as the inverse scramble sequence.
 - E3d+) [CLARIFICATION] Any stopwatch or watch used by a competitor must not have any functions that would help the competitor find a solution.

wca-regulations.md

@@ -313,9 +313,9 @@ Note: Because Article and Regulation numbers are not reassigned when Regulations
         - 12a2b) Counter-clockwise, 90 degrees: nFw', nBw', nRw', nLw', nUw', nDw'.
         - 12a2c) 180 degrees: nFw2, nBw2, nRw2, nLw2, nUw2, nDw2.
     - 12a4) Rotations (entire puzzle):
-        - 12a4a) Clockwise, 90 degrees: [f] or z, [b] or z', [r] or x, [l] or x', [u] or y, [d] or y'.
-        - 12a4b) Counter-clockwise, 90 degrees: [f'] or z', [b'] or z, [r'] or x', [l'] or x, [u'] or y', [d'] or y.
-        - 12a4c) 180 degrees: [f2] or z2, [b2] or z2, [r2] or x2, [l2] or x2, [u2] or y2, [d2] or y2.
+        - 12a4a) Clockwise, 90 degrees: x (same direction as R or L'), y (same direction as U or D'), z (same direction as F or B').
+        - 12a4b) Counter-clockwise, 90 degrees: x' (same direction as R' or L), y' (same direction as U' or D), z' (same direction as F' or B).
+        - 12a4c) 180 degrees: x2, y2, z2.
     - 12a5) Outer Block Turn Metric (OBTM) is defined as:
         - 12a5a) Each move of the categories Face Moves and Outer Block Moves is counted as 1 move.
         - 12a5b) Each move of the Rotations category is counted as 0 moves.