[Enesuygurs]

This PR will...

Accept #EXTINF durations that have no digits after the decimal point, such as #EXTINF:10.,. The duration group in LEVEL_PLAYLIST_REGEX_FAST was (\d*(?:\.\d+)?), which requires a digit after the dot. It is now (\d+(?:\.\d*)?|\.\d+)?.

Why is this Pull Request needed?

RFC 8216 defines a decimal-floating-point as characters from [0-9] and ., so 10. is a valid duration. The old pattern only captured 10. The leftover ., (or .,title) on the same line then matched the segment URI alternative. For this playlist:

#EXTINF:10.,
segment-1.ts
#EXTINF:4.,title
segment-2.ts

master parses 4 fragments: ., (10s), segment-1.ts (0s), .,title (4s) and segment-2.ts (0s). The made-up URLs fail to load, and the real segments get a duration of 0. With this change the playlist parses as 2 fragments of 10s and 4s, and the title is kept.

Are there any points in the code the reviewer needs to double check?

• 10, 10.5 and .36 still parse the same way. The existing "without a leading digit" test covers .36.
• An empty duration or a bare . does not match the group, which is the same as before, so malformed lines behave as they did.

Resolves issues:

Fixes #8112

Checklist

• changes have been done against master branch, and PR does not conflict
• new unit / functional tests have been added (whenever applicable)
• API or design changes are documented in API.md

Unit tests: 1242 passed. The new test fails on master with 4 fragments instead of 2. lint, prettier and type-check are clean.