Update introduction vignette

[anajens]

Close #702

[anajens]

@gmbecker here is a very rough draft.

I looked into the data packaged in ggplot2 and I think suitable datasets to use would be either mpg or diamonds. Overall both of these are more complicated than what is needed so I decided to leave the example data as is.

If you are OK with using an external data package, [palmerpenguins](https://allisonhorst.github.io/palmerpenguins/articles/examples.html) is a very nice alternative to iris and would work here.

[github-actions]

Code Coverage Summary

Filename                     Stmts    Miss  Cover    Missing
-------------------------  -------  ------  -------  -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
R/00tabletrees.R               744      62  91.67%   21, 102, 105, 412, 496-497, 500, 656, 757, 849-850, 951, 953-954, 977-980, 1002, 1114-1117, 1212-1217, 1365, 1462-1465, 1529-1532, 1568-1571, 1577-1582, 1632, 1639, 1739, 1852, 1866, 1869-1872, 1875-1878, 1906, 1937-1938
R/as_html.R                    161      25  84.47%   5-10, 74, 131-136, 141-146, 161-165, 253
R/colby_constructors.R         558      20  96.42%   71, 123, 181-184, 244-247, 387, 404, 1213, 1306, 1468, 1506, 1528, 1552, 1573, 1729
R/compare_rtables.R             83      17  79.52%   93-96, 99-102, 115-118, 137, 157-158, 189, 194
R/format_rcell.R                12       0  100.00%
R/indent.R                      13       2  84.62%   39-40
R/index_footnotes.R             66       0  100.00%
R/make_split_fun.R             119      23  80.67%   22-25, 51-54, 57-60, 115, 119, 280, 283-286, 291-294, 313, 412
R/make_subset_expr.R           136      14  89.71%   34-48, 126-133, 168, 250, 266, 274
R/simple_analysis.R              5       1  80.00%   55
R/split_funs.R                 505      66  86.93%   143, 148, 154-159, 164, 181-185, 366-371, 388-393, 474, 526, 544-547, 564, 631, 641-642, 644, 658, 702, 727, 903, 910, 936-939, 950-951, 953, 955, 1126-1128, 1142-1146, 1210-1213, 1276-1279
R/summary.R                    215      24  88.84%   38, 85, 192, 200, 271-276, 287-288, 307-308, 418, 465-481, 516, 549
R/tree_accessors.R             946     102  89.22%   109, 251, 269, 292, 330, 344, 360, 465, 492-493, 774-779, 907, 925, 949, 999, 1054-1055, 1094, 1127, 1163-1167, 1220, 1295-1299, 1317-1327, 1396, 1501-1504, 1529, 1549-1550, 1559, 1600, 1618-1622, 1643-1647, 1726, 1768, 1872, 1976, 1989, 2002, 2016, 2024, 2033-2037, 2379, 2737, 2850, 2883-2905, 2994-3001, 3156, 3229-3234, 3443-3444, 3451, 3454-3457, 3461, 3512, 3546, 3571-3595
R/tt_afun_utils.R              411      32  92.21%   50, 164, 171, 181-194, 260, 271-272, 504, 512-515, 597-601, 622, 637-639
R/tt_compare_tables.R           70       4  94.29%   56, 178, 257, 261
R/tt_compatibility.R           510      56  89.02%   19, 142-143, 192, 197, 332-333, 337-340, 346, 350, 398, 520, 568, 601, 621, 654-657, 701, 718-722, 809, 837-840, 849, 912, 920, 931-934, 1044, 1051, 1080-1094, 1125-1126
R/tt_dotabulation.R           1117      96  91.41%   54, 252, 257, 259, 310, 334, 338-341, 373-376, 399, 434-437, 465-468, 565, 702-706, 756, 760, 789-792, 802, 822-826, 833-836, 1095, 1099, 1130, 1243-1246, 1442-1450, 1591, 1675-1684, 1764-1767, 1778, 1783, 1788-1789, 1791, 1802, 1807, 1830, 1925-1944
R/tt_export.R                  465      34  92.69%   44, 173-177, 216-219, 261-264, 316-320, 385, 439, 732, 741, 766-770, 937-940, 943, 974, 980
R/tt_from_df.R                   9       0  100.00%
R/tt_paginate.R                440      37  91.59%   45, 70, 107-115, 396, 518-521, 541-545, 695-698, 748-755, 824, 827, 837, 844, 847
R/tt_pos_and_access.R          571      43  92.47%   77, 79-81, 106, 166, 212-216, 262, 515, 517, 525, 531, 545, 555-558, 740, 751-755, 760-763, 790, 843-844, 856, 1022-1023, 1081-1109, 1389, 1466
R/tt_showmethods.R             144      21  85.42%   60, 97-120, 183, 209, 218, 226, 229-233, 326-327
R/tt_sort.R                     88       5  94.32%   223-226, 234
R/tt_toString.R                395      25  93.67%   115, 306, 356, 371, 381, 388, 391, 397-407, 495, 560, 566, 801-827
R/utils.R                       29       0  100.00%
R/validate_table_struct.R       84      10  88.10%   79-83, 92-93, 140, 150-151
R/Viewer.R                      61       9  85.25%   47, 51, 61-65, 85, 119
TOTAL                         7957     728  90.85%

Diff against main

Filename                     Stmts    Miss  Cover
-------------------------  -------  ------  --------
R/00tabletrees.R              +120     +21  -1.76%
R/as_html.R                    +73     +18  -7.57%
R/colby_constructors.R         +76      +3  -0.06%
R/compare_rtables.R             +5      +6  -6.38%
R/index_footnotes.R            +16       0  +100.00%
R/make_split_fun.R            +119     +23  +80.67%
R/make_subset_expr.R           +30      +2  +1.03%
R/split_funs.R                 +84     +11  -0.01%
R/summary.R                    +32      +8  -2.42%
R/tree_accessors.R            +153     +34  -2.21%
R/tt_afun_utils.R              +66      +7  -0.54%
R/tt_compare_tables.R           +5       0  +0.44%
R/tt_compatibility.R           +97      +6  +1.13%
R/tt_dotabulation.R           +380     +52  -2.62%
R/tt_export.R                 +236     -39  +24.57%
R/tt_paginate.R                +57     +22  -4.49%
R/tt_pos_and_access.R          +51      +6  -0.42%
R/tt_showmethods.R             +23       0  +2.77%
R/tt_sort.R                     +7      -1  +1.73%
R/tt_toString.R                +90      +3  +0.88%
R/utils.R                      +18      -1  +9.09%
R/validate_table_struct.R      +84     +10  +88.10%
R/Viewer.R                      +5       0  +1.32%
TOTAL                        +1827    +191  -0.39%

Results for commit: 008768b

Minimum allowed coverage is 80%

♻️ This comment has been updated with latest results

[github-actions]

Unit Tests Summary

       1 files       24 suites   1m 29s ⏱️
   197 tests    197 ✔️ 0 💤 0 ❌
1 506 runs  1 506 ✔️ 0 💤 0 ❌

Results for commit 008768b.

♻️ This comment has been updated with latest results.

[ayogasekaram]

looks great! Thanks @edelarua